I got 14/151 (charizard, squirtle, pikachu, raichu, meowth, psyduck, golduck, geodude, slowpoke, goldeen, seaking, snorlax, mewtwo, mew and missingno) from watching the cartoon on TV 25 years ago and never playing the games. I also remembered rattata, poliwhirl, diglett and koffing but spelled them one letter off so that's pretty much 18/151