From Mario Fan Games Galaxy Wiki
Sprite Database (SDB) is a sprite resource website created and maintained by Grim. It is an alternative to MFGG's affiliate, The Spriter's Resource (tSR). Although SDB has less content than tSR, it has many quality sprite sheets that tSR doesn't have, and is regarded by some as being "more professional" in the way it handles its content. Also, as well as offering just sprite sheets, it also hosts sound rips, tutorials and useful programs.
As The ShyGuy Kingdom has become inactive over the last few months, many see Sprite Database as being the second-best sprite resource site after tSR.