>>36263796Continued
>Oddish lineLearns Sleep Powder and Stun Spore early. Is inferior to the Bulbasaur line in every other way. At least it learns Cut. I'd rank it with the Weedle line, since it's situationally useful.
>Gastly lineEven if you can't evolve it to Gengar, Haunter is still great. Immunity to Normal (and to a lesser degree, Fighting) is incredibly useful, and it has a nice Special stat as well as good Speed. Teaching Thunderbolt to Nido or the ghost is maybe the hardest choice here, but there's always Thunder for the other one. Gastly also learns Psychic.
>Venomoth lineSimilar to Oddish, but with a slightly different typing and access to Psychic-type moves (by level-up, no less) instead of Cut. Not awful, not great.
>Tentacool lineGreat Special stat, good Speed, decent movepool, and it might even be a guaranteed encounter. The bad news is that it's only guaranteed if you're Surfing, which takes a moveslot from Nido. Surf for STAB and HM utility, Blizzard or Ice Beam for coverage, maybe Wrap, maybe Hyper Beam, maybe Swords Dance? Do what you want, it's great. If you don't want to teach your Nido Surf, you can catch it with Super Rod on certain routes, but that's only a 25% chance.
>Koffing line/Grimer lineYou'll most likely find Koffing, since you're playing Red, but they're fairly similar. Bulky, mono-Poison, similar movepools. Both can go with Sludge and Fire Blast (nothing else wants that TM anyway). The rest is up to you. Since you find them so late, they're not actually that useful.
tl;dr Venusaur, Nidoking, Arbok, Haunter, Tentacruel should be on your final team, the sixth is filler (or something that knows Cut).