Com Mons

The Mon/card for beginners. Common, that is. In Video Games, they show up early in large quantities, but quickly grow useless - unless some Magikarp Power is applied and with time and care, you can make some pretty powerful fighters out of them. In trading cards, the cards that are only good for firewood.

Polar opposite of Olympus Mons.

Eastern RPGS

 * Rattata and Pidgey in Pokémon, as well as all the others based on them. (Yes, Hoothoot, Sentret, Poochyena, Taillow, Zigzagoon, Starly, Bidoof, Patrat, Lillipup and Pidove, we mean you.) Also Zubat and Geodude, which can be caught early on in all generations (excluding Pokémon Black and White) and continue to show up in every single cave you enter throughout the game.
 * On the subject of Black and White, Roggenrola (and its evolution, Boldore) and Woobat are pretty much Unova's equivalent of Geodude (or Graveler in Boldore's case) and Zubat, respectively. The fact that Woobat's name rhymes with its Gen I-IV counterpart's makes it more obvious that it's the latter's counterpart.
 * However, almost all of these pokemon will stay as useful party members for a long time if you train them up. On the other hand, many Bug-types like Caterpie, Weedle, and their various Expies can also be caught very early on and evolve quickly (they reach their final evolution at level 10. Your starter generally won't get there until level 36). But they are just as quickly out-paced in terms of stat growth and movesets by other pokemon, so many players will just pass them up entirely.
 * And definitely Magikarp, at least until it evolves.
 * Full aversion with Starly and its evolutions, which are incredibly useful at all stages of the game, and can be caught on the very first Route.
 * Also an aversion with Lilipup and it's evolutions which becomes an incredible attacker/tank as Stoutland and has great abilities in Intimidate and Sand Rush. Just like the Starly example above, it can also be caught on the first route.
 * Mocchi in Monster Rancher 2, however Monster Rancher is built on Magikarp Power, so it can become quite badass.
 * Specificaly Knight Mocchi (Mocchi/Durahan), due to installshield (I think, it might be another major installation program) based installation discs shrining as them, with Melon Suezo (Suezo/Zuum) comming in a close second.
 * The catch ? In Monster Rancher 2 Melon Suezo is alvailable from the start, has awesome offensive stats, +1 life, good lifetype, decent lifespan, lots of spammable move with decent damage, and easily combined for awesome monster with normal Suezo. Mocchi on the other hand have stats that outclass every other species bar none. YES, the monster you can get by going to the market is after all the strongest monster in the game. Sadly the movepool is horrible
 * Hares. At least in Evo. It seems like you get one every couple of disks or so. That doesn't mean they're any weaker than, say, a Phoenix however.
 * Romby and Ramby from Robopon. Even in high-level dungeons, you'll still find them. And because the game is Nintendo Hard, they'll still kick your ass.
 * Slimes in the Dragon Quest series. A basic slime will always follow you into every world or island you visit, no matter how tough the natives are. However, thanks to Hot Skitty On Wailord Action, you could use some REAL Magikarp Power.
 * Slimes do have a few things going for them -- First, in every Dragon Quest Monsters game, you can breed a King slime using basic slimes and a lot of patience; King slimes tend to be pretty powerful (they are basically given skills similar to the main series' heroes -- lightning, healing, revive, etc). Slimes themselves make good mates for other monsters -- in the original two games, Slime + anything meant a special kind of Slime, like Wingslime, Rockslime, Drakslime, all of which tended to be somewhat useful. But the thing slimes really had going for them is that, if you leveled them up enough, they learn Mandante -- Megamagic in the US version, a spell that uses up all your Mana at once to hit the enemy with a huge blast.
 * Two slimes plus total + level (That's deliberate.) of 5 or more = King Slime. Damn, DQM took HSOWA to bizarre levels.
 * In Joker 2, this is actually lampshaded. Breeding 2 slimes of a certain level will result in a Stronger slime, while breeding together 2 stronger slimes of a certain level will result in a Strongest slime.
 * Wumps in dungeon-crawler Azure Dreams.
 * Megaman Battle Network adds rare viruses, in which Rare Mettaur stands out.
 * Also, in the same series, there is a battlechip called Area Grab that is part of your starting folder in every single game. However, Area Grab is usually the only battlechip in the games (baring Metagel in 3) that will allow you to take over part of your opponents territory (thus expanding your movement area and opportunity to evade attacks while reducing your opponents and even increase the power of some attacks'). This means everything to most players, everything to the point in which one in * code is considered far more valuable than any Infinity Plus One Sword battlechip. The rest of the starting battlechips (outside of the attack +10s in 2 and 3, and then only for folders that contain multihit attacks) in are commonly viewed as Vendor Trash instead.
 * Well except for the basic Sword trio, and even then it's only because of one thing: Life sword. The first Program Advance you can use, making it one of the most useful attacked in the early game.
 * Guard/Reflect * . The one chip you're guaranteed to have 99 of at some point in the game. Lampshaded at least twice - in EXE 2, when in a foreign country, a kid asks you to get him a Guard *, because they're super rare there. However, all your spare chips have been stolen; if you don't have one in your folder, you can talk to a tourist from your country, who gives you 30 Guard * chips! If you talk to her again, she says: "No need to thank me, I still have over 1000 'Guard *' chips". Later in the sixth [?] game, someone gives you a good chip in exchange for 30 Reflect * as part of a mission.
 * While Shock Wave and Guard chips in early games are mediocre at best, Reflector chips in Battle Network 6 can be incredibly useful while in good hands. They are easy to get (and S busting rank on Rare Mettaur 2 nets you a Reflector 3 chip in * code. You can put four in one folder and one deals 200 damage). What makes them so good is that unlike in older games, where guard chip reflected a shock wave at the opponent, in BN 6 they reflect a very fast shot instead. This means that with correct timing you can block enemy attack AND get a counter hit easily, which puts you into full synchro mode (next attack deals double damage) and the enemy is stunned for a few seconds, turning the flow of battle heavily in your favor. And ff you follow it with multi-hit chip like Super Vulcan, Risky Honey or Bass chip and some Attack+ and Color/Double point chips (which add massive damage on multi hit chips, and all of this is doubled with full synchro), you can instantly kill ANY BONUS BOSS with a single attack chip!
 * Disgaea provides Prinnies (dood!), which are a waste of time to level up and train. However, if you keep their HP high, they make excellent grenades in a pinch.
 * They're also useful because, in combos, damage increases with each hit. Prinnies in combos hit a hell of a lot. Therefore, adding any to a combo quickly ranks the combo up to especially high damage.
 * Not to mention, cheap to maintain. No matter how strong they are, it's still only 1 HL to restore them to full health, even if they used up all of their SP and then got killed.
 * Prinnies also level at an obscene rate.
 * Also any class can transmigrate to them, and they can transmigrate to any class. (Normaly human-types cannot transmigrate to demon-types and vice versa)
 * Almost any lower tier of a character class could be considered this Trope, considering how cheap they are to create compared to the higher tiers and how much weaker they are, especially without any reincarnations.
 * Early in The World Ends With You, you're given an assortment of weak pins describing a wide swath of the game's gestures and damage types. If you try to sell one, you're told it's "more valuable than all the yen in the world". (The real reason, of course, is that having no pins makes it almost impossible to win battles to get more.)
 * Pixies in Shin Megami Tensei, particularly the MMO Imagine. You usually get them fairly early on, they're easy to negotiate with, and you'd never use one in a fight unless you want to die a horrible death. They are fairly useful in fusion though, as many powerful demons have a pixie somewhere in their ancestry. Nocturne is unique in the main series in that they give you a single pixie who, if you hold onto it until near the end of the game, will evolve into an Infinity Plus One... Pixie.
 * Shin Megami Tensei Strange Journey is notable in that you will be using Pixie until well into Bootes. You don't get Fire and Healing magic on the same demon very often in this game, and she's strong against fire. Guess what every other demon uses? (Once you meet Mitra, though, it's time to look into her fusion options.)
 * There's a password released by Atlus for a pixie that's Lv. 1, but has 10 MAG (Pixies have 3 at level 1) and 99(!) LUC. It knows Megidolaon (a hyper-powerful non-elemental magic attack), and Mediarahan (a party-wide full heal). It costs a smaller fortune to summon, but around the 4th and 5th zone, it can be leveled quickly and you have a Glass Cannon at your disposal.
 * The password is "Madeka Ueno"
 * The lowest-level basic types in Gotcha Force all behave like this - the Normal Ninja, the Revolver Gunman, the Battle Girl, the Wing Soldier, the Normal Tank, the Normal Knight, and the Normal Samurai will clog your collection before you know it.
 * Obscure Game Boy RPG Lil Monster has numerous ones, available from the start. They're spawned from the "basic attack" gems, like Punch, Kick, Needle, Catcher, and Heal. They can be fought in lots of different ways, their attack is unremarkable, and you'll have a million of their gems in no time.
 * Applies to Final Fantasy Tactics, in the form of Invited enemies and soldiers. The only human enemies you can invite are ones with Squire as their base class (as opposed to certain characters having Holy Swordsman, etc). Likewise, unless you're lucky with random battles, the most common monster types are the least useful.
 * Although this is averted when you reach hell. All the characters you can invite are actually useful and have a decent amount of good skills. Of course by that point in the game, who cares?

Western RPGS

 * If you're playing Geneforge as a Shaper, the cute little lizards known as Fyoras will be your first Monster Allies, and will almost inevitably be replaced with Drakons or the like by game's end. This is averted if you're a more physical class, though--either you'll do a Solo Character Run, or you'll get a Fyora and level it until it can nibble a Drakon to death.

Collectible Card Games

 * Played straight in the Final Fantasy VIII card game, where you start with a crappy collection of cards and then have to play other people and sift through their horde of bad cards to get one of the few worth having.
 * However, the whole point of playing cards in the game is for refining said cards into items, so every card has some sort of use.
 * About a third of the iconically bad cards in Magic the Gathering are common. Almost all of them are creatures that would have been fair at half their mana cost.
 * In Time Spiral's bonus Timeshifted set, the old "Squire" card, legendary common of badness, was treated by players as a curse at worst, a booby prize at best.
 * The designers of Magic are rather diligent at making sure rarity doesn't equal usefulness, for several reasons. To put in perspective, when players complained about the quirky rare "Steamflogger Boss" being total junk, demanding it should have been downgraded to uncommon, one response from Wizards was "you hate this card so much, you want more of them to show up in your packs?"
 * Also, many tournaments are booster drafts, where much of your deck is going to be commons anyway. If the majority were useless, those would be some damned unfun tournaments.
 * Casual players often forget/don't realize that much of a set is designed to have fair and fun "limited" tournaments (the varieties of play in which you open new packs and build decks out of those cards only). Tournament players, in turn, often forget that much of a set is designed for casual play. Thus, a lot of cards get accused of being "useless" that really aren't, they're just for a different audience. Of course, there is still the occasional complete trash - but usually it's no more than 1 or 2 cards in a 200-card set, and like good and evil, good cards cannot exist without bad cards to compare them against. Of course, I speak of MODERN Magic. Go back to the mid-90's and there's all kinds of terrible Com Mons, such as the aforementioned Squire.
 * Yu-Gi-Oh provides reams of monsters which even type specialists won't go near. One wonders why they bother wasting the paper. In particular, Normal Monsters are generally ignored unless they have notable stats (which keep creeping upward), and tribute monsters usually require some kind of great effect to be worth it.
 * While it was always like this from the start (licensed merchandising trumping game balance, one assumes), it got especially bad once the US game caught up with the Japanese. Suddenly in each seventy-odd card set, only a half-dozen were remotely more useful than what was already available, and most of those were terribly unbalanced ultra rares that were guaranteed to be banned within the year.
 * In all fairness, though, recent sets have been somewhat dutiful to making these kinds of cards at least somewhat useful; for instance, there are plenty of support for Normal Monsters to make a viable and powerful deck out of them, whether it be a sheer beatdown or weenie rush. That's not to say that they don't still give out crap, on occasion.
 * Also, as mentioned above, Power Creep hasn't exactly helped. These days you have Lvl 4's that are more powerful than the old Level 5's and now certain Lvl 3's (Tune Warrior, X-Saber Airbellum) are stronger than some of the old Level 4's. And let's not forget poor Red-Eyes, who's a Level 7 Normal Monster and there are Level 6 Monsters that have the exact same stats for one Tribute less (like Amphibian Beast).
 * Chainsaw Insect is even worse, a level 4 with 2400 attack, 0 defense, even Muka Muka which is a low level (and actually is pretty old) that could get that strong by its effect wasn't always and how often are you going to use Chainsaw Insect in defense? Poor, poor Red-Eyes.
 * Not to mention that they remade a couple old notable cards by giving them adjectives to their names to make them have any sort of purpose in the modern game. The Obnoxious Celtic Guard is a remake of a pathetic card with only 1400 attack points and gives it resistance to being destroyed by strong cards. Swift Gaia the Fierce Knight takes a monster which is disappointing for requiring two tributes and gives it the ability to sometimes be summoned WITHOUT a tribute.
 * On the subject of new Gaia's, there's this and this. Both are much stronger than the original.