Using "Fixed Moveset" Pokemon. Pokemon that can only learn 4 or less moves, which include:
-Caterpie (Tackle, Stringshot)
Higher Attack and Speed than Metapod
-Metapod (Tackle, Stringshot, Harden)
Higher HP, Defense, Special Attack, and Special Defense than Caterpie
-Weedle (Poison Sting, Stringshot)
Higher Attack and Speed than Kakuna
-Kakuna (Poison Sting, Stringshot, Harden)
Higher HP, Defense, Special Attack, and Special Defense than Weedle
-Magikarp (Splash, Tackle, Flail)
Has High Speed, but nothing else, really.
-Ditto (Transform)
Transform into Stronger Opponents
-Unown (Hidden Power)
Can help cover other types with Hidden Power that the others can't.
-Wobbuffet(Destiny Bond, Counter, Safeguard, Mirror Coat)
It's not Uber in GSC, due to the lack of Encore and Shadow Tag. But it's worth a try.
Delibird and Smeargle could be used, to, due to lack of Variety of Level-Up Moves(Although Smeargle, with its one Level-Up Move, can lean a large variety of moves).