http://xcopy.tumblr.com/
http://mrdiv.tumblr.com/
These are 2 blogs I found on Tumblr, both working in abstract motion design. Personally I prefer mr. div because there's a greater variety in the works he produces. xcopy loses points from me because their gifs make me a little dizzy.
Coincidentally, here's my Tumblr. account http://kulum.tumblr.com/