Scraggy is a rather interesting-looking gen 5 Pokemon, vaguely lizard-like in appearance. Dark/Fighting type. It evolves into Scrafty, also Dark/Fighting.
Mienfoo is a pure Fighting type, also fifth gen, and evolves into Mienshao, which retains the pure fighting typing
Then there's Croagunk from gen 4 which evolves into Toxicroak, both Poison/Fighting.
Next we have Meditite and its evolution, Medicham, a pair of Fighting/Psychic types from the third gen.
And finally, from the first gen, the Poliwag line... a bit different from the others, but we have:
Poliwag, a pure water type, which evolves into Poliwhirl, another pure water type, which can further evolve into either Poliwrath, a Water/Fighting type or Politoed from the second generation, who retains its pure water typing.