Do you want suggestions for 2d or both 2d and 3d and Japanese or NA/EU games? There are probably too many if you include 3D platformers.
2D platformers in the PSX? You can't do better than the Megaman X Series, though there's also Gunners Heaven, which is awesome. There's also Klonoa, which is classic (and there's Klonoa 2 on PS2 which is also very good). I don't know if Silent Bomber counts as a platformer, but it's a top down 3d bomberman thing, with jumping and shooting involved, and I like it a lot. For a 2.5D quick fix that you can finish in under twenty minutes, there's Strider 2. And there's always those Metal Slug ports, too...