I'm doing quite a fun challenge right now. I am prohibiting myself from using any pokemon, any moves or any items (in battle) unless they are introduced in that generation. Starting in gen 2. With a level limit to stop overlevelling
This means I used 3 Unown to beat Falkner, Hidden Power was my only available gen 2 move. After Falkner my Cyndaquil could learn Mud-Slap!
Also needed that same Unown with HP Fire to beat Bugsy...
And to beat Morty I had to breed an Eevee, evolve it to Umbreon before level 16 to get Pursuit. So now I'm grinding that.
My Return Granbull wrecks stuff, Quilava's best move is Rollout (until I get Flame Wheel) and Umbreon has Nightmare/Attract just to get rid of another 2 earlier gen moves
This is harder than it seemed at first xD
That's some dedication. Good luck with finishing it.
Honestly, it adds a proper challenge and some thinking to an otherwise easy game.
Right now it's almost casual, just not having optimal movesets and coverage with my 4 Pokemon. I'm considering catching Skarmory, but it will suck until Kanto when it gets Steel Wing. it's not that great, maybe I'll stick with Typhlosion, Granbull, Umbreon and Lanturn