Game Art

Liberated Pixel Cup

Free, video, download, documentation, demo, source of demo.

Lost Garden

Free, tutorial

Small World Realms

For inspiration, site

Infographics from Yandex

For inspiration.

Hieroglyph

For inspiration.

Fantasy & Sci-Fi Sprites

Paid (but very cheap), download

Hard Vacuum

Free, download, there's also a game that uses it Mini Tower Defence.

Art from Buch

Free, download, site

Sketch Warriors

For inspiration, play.

Sketch Fighter

For inspiration, play, video,

Some Drawings

Nice and extremely simple Top Down Map

Even simpler map, demo