We just released our latest tileset, a blocky, pixel art, 8-bit style perfect for platformers:
https://rumblecade.itch.io/platformer-tileset-8-bit-style
The full tileset has a lot of options for variants built in, and even includes alternate palette versions. Also included are .tmx and .tsx files. We've tested it thoroughly in Tiled Map Editor and the terrain brush makes quick layouts a breeze. Then comes the fun part, adding all the little details and objects that can be used in many different ways. Enjoy!