I ran some checks on my database (it has the data of exactly which pokemon learn which moves so I can get stats from it) and found that there are 12 moves learnable by 481 pokemon, and 2 by 480 pokemon (next down is only 427 pokemon).
481:
Swagger, Natural Gift, Secret Power, Facade, Double Team, Substitute, Sleep Talk, Toxic, Endure, Hidden Power, Frustration, Return
480:
Protect, Rest
The pokemon that can't learn those moves are:
Caterpie, Metapod, Weedle, Kakuna, Magikarp, Ditto, Unown, Wobbuffet, Smeargle, Wurmple, Silcoon, Cascoon, Wynaut, Beldum, Kricketot, Burmy, Combee
(And Regigigas can't learn the other two)
