It's my tileset, this time with fixed problems and new things.
There is a lot of info here. You can read it in the .txt file.
This is version 1.5. Here are the changes:
-replaced the swooper from version 1.0 with a magikoopa. Has better shading than the swooper. The sad part is that the frame and the glasses share the same color. You'll have to plan around that;
-the columns for the FG now have a black outline, meaning Mario can't pass through them;
-the Map16 for the BG has been optimised. By moving two tiles around, I made the magikoopa easier to insert into the BG;
-moved the second FG palette to palette 5, freeing palette 4. Now cement blocks, midway points, midway tapes and goal posts can be used;
-the pipes and munchers have darker colors now;
-merged the ExGFX, Map16 and palette files into their own folder, making those easier to find;
-the other parts of the layer 2 palettes can be assigned to the magikoopa for different looks.