Mankey learned Meditate
Vulpix can get Hypnosis as a GSC tradeback.
Bellsprout can get Lovely Kiss as a NYPC
Cubone, can get Rock Slide
Exeggucute doesn't get Mega Drain in RBY, but in GSC. I think Exeggucute is just a Psychic type and not a dual Grass type.
Ponyta get Double Kick also, and Hypnosis
Butterfree up your day, because I'll bedrilling you all night