sofar (CC BY-SA 3.0):
default_book_written.png, based on default_book.png
+ default_aspen_sapling
+ default_aspen_leaves
+ default_aspen_tree
+ default_aspen_tree_top, derived from default_pine_tree_top (by paramat)
+ default_aspen_wood, derived from default_pine_wood (by paramat)
Neuromancer (CC BY-SA 2.0):
default_cobble.png, based on texture by Brane praefect