Boring but Practical

Everyone loves flashy magic, BFGs, and big, thundering tanks. However, the more interesting something is, the more likely it falls victim to the rule of Awesome but Impractical: You can't use it often enough, it costs too much, or it just takes too much effort to get it. You could even have Cool but Inefficient, where it just looks awesome, but that is about it.

Tim-Tom: We leave the gas on... They go in their sleep, all quiet-like --
Kevin: Aw, I wanted to hear 'em scream!

Tim-Tom: It's not as much fun, but it will look more like an accident.

—The Venture Brothers

Therefore, we have things that are much more "boring" and normal, but these things often contribute more to your success in the long term than the visually more impressive things.

May border on Game Breaker. Compare Awesome Yet Practical. Contrast Awesome but Impractical, Cool but Inefficient.

Examples of Boring but Practical include:

Video Game Examples:

Healers in MMORPGs are often this. Fiery doom or big swords are a lot cooler, but you try getting anywhere in a dungeon without a dedicated healer in your group. (However, a lot of video games try to circumvent this by giving healing spells effects just as spectacular as their offensive counterparts, such as big shining lights, summoning gods, or massive plant growth.)
Same for medics in FPS games that have them. In addition, ammo limitations often make normal guns more useful than sniper rifles or the BFG, or other restrictions on those weapons may render them impractical.
... and, working backwards through history, healers in almost any pencil-and-paper roleplaying game.
Similarly, weapon loadouts that don't require much ammunition or allow you put a ton of ammunition on your vehicle in things like Humongous Mecha combat sims. The bigger guns tend to be unable to stock much ammo and take up more space, besides.
Normal attacks in RPGs. Special moves and magic are a lot more flashy, but they are usually restricted by something or other (Mana, Limit Break, etc). And some spells might not even work when you really need them.
In platformers, Goomba Stomp or basic moves, as opposed to the things you can do with powerups. Vital since the said powerups aren't always available, and if you lose yours mid-level, what then?
In strategy games, the basic combat unit is usually more efficient than the larger (and cooler looking) counterparts. Tournament players will often make heavy use of rather basic units in general. Any type of rush depends on this trope.
Again, in strategy games, Worker Units. These guys have little or no combat capability and present easy targets for your enemies, but without them, you have no economy, and without an economy, you have no army.
Many action and brawler games with unlockable movesets usually fall prey to this. Players are so accustomed to the initial attacks that most new moves are too foreign to properly use or experiment with.
- This is often particularly true when button combos are required. By the time the new moveset is unlocked, the enemies are too powerful to take lightly by practicing your new attack on, and your own damage output is high enough that failing to activate your new ability will simply kill a mook outright with a mere jab.
The Jack of All Stats can often be this trope; they may lack the coolest, or strongest moves, but are fairly good at most attributes, and lack the glaring weaknesses of other character types.

Other Examples: