List of neat art programs, tools, and references I've discovered.

Kuadro

Tool for managing reference images.

PureRef

Tool for organizing and viewing reference images. Similar to Kuadro.

Crocotile 3D

A neat little program to build 3D scenes with 2D tiles.

Sprytile

Inspired by and similar to Crocotile 3D. An add-on for Blender.

Animal Photo Art References Search

A very neat tool to use to find animal references created by x6udpngx.

Lospec

A site dedicated to pixel art. Full of art resources and tools.