It seems like everyone (by everyone meaning 2 other people) is posting their tilesets, so here are mine:
(http://g.imagehost.org/0242/Tileset249.png)
(http://g.imagehost.org/0625/Tileset250.png)
This is my personal fave <3
(http://g.imagehost.org/0520/Tileset251.png)
It was my first attempt at trees. It failed.
(http://g.imagehost.org/0424/Tileset252.png)
My first tileset evar :D It's meh, but Carn used a modded version (by Teper) for his Journey Through Bliss.
(http://g.imagehost.org/0228/Tileset254.png)
If you do use any of these tilesets in your level, please credit me.