I can't take credit for any of these, but I'm using them in a project that wants 32x32 tiles, so I thought it might be convenient for people if I uploaded the enlarged and arranged versions of these tilesets. 

Credit information:

• The cave, desert, sewer, and overworld sets are by MrBeast
• The interior tileset is by RedShrike
• The Town tiles are by Surt, modified by Blarumyrran
• The snow town tiles are a modification of the above town tileset by Sharm
• The forest tiles contained in the town set are by Sharm.
• If you use these sets together, in addition to crediting the authors, you must also include a link in your credits to http://opengameart.org

These tilesets can be found individually in this collection.