Animals for Pixel Adventure.
Well, it says it's a space shooter creation kit, but I have in mind a strategy game along the lines of Master of Orion. Lots of asset packs collected together in a complete bundle. Having seven levels of "evolution" of each ship is a nice touch.
Part of a bundle for a hex-map strategy game with four factions. Everything you need except the game itself.
Part of a very nice pixel-art platformer bundle with nine playable heroes, 30 enemies, several bosses, animated magic and traps, complete with icons and avatars and UI.
Hex map tiles suitable for an artistic strategy / RPG.
Lovely little collection of packs for a fun platformer.
A ton of tile and sprite packs that combine to form a very comprehensive JRPG asset library. All very clean and work together well.
Everything you need for your City Simulator, except maybe trains. Tiles stack to form complex high-rise buildings, so you need proper bitmapped graphics and not just a tile-based game builder.
Complete set of tiles, sprites, and UI for a Civilization-style turn-based strategy.
Very comprehensive modern interior tileset. Clean, detailed, and frequently updated. Also includes a few animated characters.