Keyframe MP is is a compact, yet powerful, media player designed to meet the needs of animators. Features include scrubbing (with audio), single frame stepping, an adjustable playback range and bookmarks. Free Trial available.
Keyframe MP
Iamag.co
Iamag.co is a huge collection of references for walk cycles. The collection contains illustrations, sketches, model sheets and tutorials…
Posemaniacs
Posemaniacs is good free resource for searching for specific poses at various angles. It has 1000s of poses displayed by male and female 3D models.
LOLKing
LOLking is a website that can be used to view League of Legends characters and their animation sets. Great as a source of game animation reference!
Eadweard Muybridge
Eadweard Muybridge was known for his photography of humans and animals in motion, a lot of which can be found on google and is a great resource for reference material
Framepool (FREE+)
Framepool is a footage collection run by filmmakers and has a huge array of stock footage useful as reference material. It can be previewed for free or a higher quality version can be bought.
GettyImages (FREE+)
GettyImages has a massive selection of stock footage and is an amazing resource for reference material. Previews can be watched for free or you can pay for a higher quality version.
Animator's Resource Kit 