Concept Name: Suddenly Signature Ability
Description: Introducing a future gen ability and designing a Pokémon around it for exclusive use
Justification: Yes, this is another thinly-veiled attempt at getting Protean Kecleon into this metagame, but that's not all this is. Probably even more so than moves, there are a ton of very interesting abilities from future generations that could or would be potentially problematic if they were distributed to multiple Pokémon, like Protean, Moxie, Stamina, Corrosion, No Guard, etc. However, if we design a specific Pokémon to use these elements in a balanced way, then we'll have a very fun to use and interesting new part of the metagame on our hands
Concept Name: Viable NFE
Description: Buffing a Not-Fully Evolved Pokemon to OU viability while differentiating it from its evolution so it's not outclassed
Justification: Since the Eviolite doesn't exist in this gen (not that we want Eviolite Chansey or Gligar to exist, please don't add Eviolite), no NFEs currently sniff OU viability, with the closest being Chansey, who would be amazing if Blissey didn't exist, and Type: Null, who can be a nasty wincon with Iron Defense and Swords Dance since it can't get crit but is just a worse CurseLax at the end of the day. Oh, and Clamperl sees minuscule use as a Baton Pass recipient, I guess. Thus, buffing an NFE could be interesting as not only would it add another viable Pokemon, it makes for an interesting challenge in that you have to consider that any moves you add to the NFE also get added to the final evolution, not to mention an inherent BST limit as prevos can only have the same or less BST than their evo, so you really have think about the changes you make. Also, for the likes of Porygon2 and Magneton, if you add their evolutions without outclassing them, then technically you also created a viable NFE in the process, so that's an option as well
Concept Name: Steel-type Coverage User
Description: A Pokémon that has desirable Steel-type coverage, whether it has STAB on it or not
Justification: Steel, while a notoriously amazing defensive typing, is probably the worst offensive typing in the game by a wide margin. Steel is only super effective against Rock and Ice, which are both already covered by the amazing offensive typing of Fighting while being resisted by the ever common Electric, Water, and itself. Plus, the only widely distributed Steel-type moves are the unreliable Iron Tail, Hidden Power Steel (which is outclassed by HP Fighting), and Meteor Mash, which is limited to Metagross and Mawile (and Clefable, I guess). Thus, currently the only Pokémon that ever think to use Steel coverage are the Meteor Mash users. However, Steel coverage has a couple useful qualities, like pretty good neutral coverage (being resisted by only 4 types to Fighting's 4 + 1 immunity) which notably makes it neutral against non-Jellicent Ghosts and Salamence and, probably the biggest boon, super effective against Aerodactyl. This combined with just how good of a move Meteor Mash is could lead to interesting applications of the worst offensive typing in the game we could explore, whether it gets STAB on it or not