LeafGreen has: Hypno, Marowak, Jynx, Hitmonchan, Omastar, Kabutops, Snorlax, Dragonair and Dragonite.
You'l have to evolve most of the previous evolutions to get these, except Snorlax, Hitmonchan and Jynx. Those are only the Kanto pokemon though. I am not sure about all the Johto pokemon you can get in the Sevii islands after beating the Elite Four, though if I remember correctly (haven't played LeafGreen in ages) you can get Natu, Ledian, Lanturn, Skiploom, Jumpluff, Granbull, Ursaring, Slowking, Piloswine, Pupitar, Tyranitar and Donphan. Again, you have to evolve most of them from their previous forms. With some of the pokemon like Smoochum, you can breed Jynx to get one. I would look up which pokemon you can get after the Elite Four, but I'm too lazy, lol.
You'l have to evolve most of the previous evolutions to get these, except Snorlax, Hitmonchan and Jynx. Those are only the Kanto pokemon though. I am not sure about all the Johto pokemon you can get in the Sevii islands after beating the Elite Four, though if I remember correctly (haven't played LeafGreen in ages) you can get Natu, Ledian, Lanturn, Skiploom, Jumpluff, Granbull, Ursaring, Slowking, Piloswine, Pupitar, Tyranitar and Donphan. Again, you have to evolve most of them from their previous forms. With some of the pokemon like Smoochum, you can breed Jynx to get one. I would look up which pokemon you can get after the Elite Four, but I'm too lazy, lol.