Kryptonite-Proof Suit

Weaksauce Weaknesses are great to exploit, but suck to have. However, clever and enterprising creatures of the night, aliens, mutants, robots or what-have-you's can create a limited resistance or immunity by counteracting its effects. Vulnerable to fire? Asbestos-fiber suit! Holy objects repel? Wear a Darwin-fish necklace! Does water dissolve you? Coat yourself in water-proof paste! This doesn't even need to be limited to clothing, a sun-blocking satellite and a Protective Charm are among many possibilities to counter their weaknesses.

Usually this resistance is limited in some way, it may be bulky or conspicuous, only works once, or rubs off over time. It's also possible for an enemy to somehow nullify the resistance with a counter... unless they have a counter to that counter.

Commonly used in response to the Kryptonite Factor when Kryptonite Is Everywhere. Speaking of Kryptonite, it certainly helps when you're trying to fight it off. Contrast Flaw Exploitation.

Examples of Kryptonite-Proof Suit include:

Anime and Manga

"Waterproof soap" in Ranma ½ protects the wearer from having their Jyuusenkyo curse triggered... until it wears off.
In Tsukuyomi Moon Phase Hazuki crafts a cat costume that blocks out all sunlight. Naturally, while wearing it she is completely blind.
In the 2017 Castlevania series on Netflix, Striga has a suit of full-body armor to block out the sunlight so she can fight off a daytime raid.

Comic Books

Superman typically fights against Metallo and other Kryptonite-powered enemies by wearing a lead suit. Sadly, it tends to tear when he exerts his full Flying Brick package.
- Pre-Crisis, Superman actually wore 'red sun block' when he went to Lexor in order to drag Luthor back to Earth and retain his powers (since he'd always gone and lost his powers prior to that) Pre-Crisis. It didn't end well.
- In the Heroic Fantasy Elseworld League of Justice, the Sovereign had golden armour to protect himself from the Crypton powerstone powering the Green Knight's ring - thereby combining "dense metal" (Kryptonite) with "yellow" (the weakness of the Green Lantern ring).
In PS238 Atlas (who is a Superman Expy, give or take a few twists) used a heavy Hazmat Suit while carrying the glowy stuff to de-power his compatriot, who was a little too belligerent at the time.

Film

There's a pretty infamous scene in the film adaptation of Blade where baddie Frost shows up in the sunlight because he put on sunblock. In another scene, and again in the second and third movies, the vampires use full-body leather suits and motorcycle helmets when they want to go out in the sun.
The vampires in Daybreakers have built a civilization around this with sun-proof cars, sub-walks, and UV-insulated excursion suits.
Similar to the Daybreakers example, The Strangers in Dark City have created a world where it's always night, so they can experiment on people without being injured by sunlight.
The Twins Effect, a Hong Kong vampire action romance film, has a similar gag to the one in Vampires Suck, though in that film, the vampires evidently didn't know that sunblock existed, and ended up having to make their own. It worked for a while, and then smoke ensues.
In Highlander: The Source, The Guardian wears a large piece of neck-armor that makes him immune to decapitation attacks, which is pretty useful seeing as how that's the only way to kill an immortal. The Spoony Experiment, in his review of the movie, admits that as ridiculous as the armor looks (making him look like a cross between Pyramid Head and a pelican), it's actually a very clever protective measure for the whole decapitation thing. Naturally, after defeating his first opponent using the advantage from the armor, the resulting Quickening causes the armor to disappear and The Guardian never attempts to replace it.
In Gremlins 2: The New Batch, the Brain Gremlin injects the Bat Gremlin with "Genetic Sunblock" which allows the latter to fly outside in the sunlight without dying.
Another vampire example comes from the source of the page image (Seltzer and Friedberg's Vampires Suck, of all things).

Live-Action TV

In an early episode of Angel, there was a ring which gave the wearer immunity from sunlight. Angel wore it one day, then destroyed it.
- And in a much more DIY example, in Buffy the Vampire Slayer, Spike had his car with all the windows blacked out.
Raj in The Big Bang Theory can never get a girlfriend because he is unable to speak to women due to his selective mutism. He's able to get around this by getting drunk. Unfortunately, when he's drunk, he acts like a bit of a dick. In one episode, he signs up to try an experimental drug that would allow him to talk to women. The drug has strange side effects, like causing him to repeat actions over and over. In the end, it wears off just as a beautiful woman is expressing interest in him.

Tabletop Games

One group in Werewolf: The Apocalypse used high-grade protective suits to survive in a lake of liquid silver (a place in the Umbra, usually used as "cure-or-kill" treatment for badly corrupted individuals, where they were sent as punishment). This was one of their many bright ideas.
Intelligent monsters (even ones smarter than animals but less intelligent than humans) in Dungeons & Dragons will often cover their weakness this way. Mid and high level spellcasters in particular are generally run with buffs for this purpose. Common examples are dragons that cast spells that give them resistance to their opposed element and liches who ward themselves against the large quantity of undead killing spells.
- The troll Oohlgrist in Temple of Elemental Evil wears a ring of fire resistance that helps shore up a troll's normal weakness to fire and a necklace of adaptation which covers trolls lacking any protection against several types of environmental hazards.
- Illithids have special damp-suits and goggles to operate on surface without drying up or being blinded.
- Spelljammer drow commonly use "Helmet of light-seeing" - which is a common helmet with tinted glassteel visor for eye protection. Since there's a constant demand, the Arcane mass-produce those for them.

Video Games

In the Punch-Out!! series, King Hippo is soundly beaten by Little Mac repeatedly punching him in the belly button. King Hippo learns from this the second time around and places a steel sewer grate over his belly button.
In Valkyria Chronicles tanks and other vehicles run not on gasoline but on a Phlebotnium power source called Ragnite which requires special radiators usually fitted onto the back. These radiators glow bright blue and are so volatile that 1 or 2 hits from a tank shell will instantly blow them up. Nobody ever thinks to surround these with armour or deflecting plates leading to every single tank having a glowing weak spot on the back. All except one guy who actually does protect this weak spot in a mission late in the campaign.. but only after having learned the hard way about this himself. Note that the player's tanks are never protected this way either.
Legacy of Kain: Soul Reaver has a partial example, a vampiric empire that releases large amounts of smoke to reduce light levels.

Web Comics

In Supernormal Step, a vampire wears a full-body, skin-tight suit in order to go out in the sun.
Vampire Cheerleaders regularly used a common chemical protection - sunscreen. Though this was said to be enough only because they're from a line less sun-sensitive than most.

Web Original

In The Incredible Hero, a continuing add-a-chapter-as-you-go story on a pre-HTTP message board, the titular hero was once attacked by Darth Vader. Luckily, he was wearing his dark-side-of-the-force-proof vest.

Western Animation

An episode of The Powerpuff Girls involves the head honcho of thing that go bump in the night, The Boogie Man, launching a giant disco ball into space to block out the sun so all the monsters can come out during the day and party ALL NIGHT LONG!
Zim of Invader Zim is burned by water, so he cooks up a paste-based film coating to protect himself.
On the Futurama episode "A Tale Of Two Santas", Leela tries to destroy Robot Santa with a paradox. Unfortunately, Santa comes equipped with paradox-absorbing crumple zones.
- Though to be fair, Leela didn't actually use a paradox.
The plot of the Cuban animated feature Vampiros en la Habana revolves around the creation of a vampire sunscreen.
Superman: The Animated Series introduced a lead-lined suit to protect Supes against Kryptonite radiation. It came in real handy during its debut episode against the Parasite. Thereafter it suffered the Worf Effect as everytime it appeared it was torn or destroyed early into the battle (dipped in magma, ripped off by Krypto, freeze cracked, acid...)
- He had a much simpler (and weirder) solution to fighting Live Wire and her electric powers... Supes pretty much just laminated himself in a thin layer of rubber, since it doesn't conduct electricity.
In one episode of the Superfriends, both Robin and a Frankenstein's Monster absorb powers from the rest of the show's heroes, including Superman; after battling to a stalemate, Robin uses one of these suits, and a chunk of kryptonite, to defeat the creature.