I love doing practice sketches :3 I use websites Posemaniacs and Pixelovely for this. Both are amazing, first one has lots and lots of 3D humans (skin-less, so you see muscles) in various poses and the second one has photos of animals and people (full-bodies and hands, feet, faces and expressions). I found The Croquis Cafe on Youtube a while ago and just left it open in a tab for until I'd want to use it. I finally decided to test it yesterday and I did 3 lessons so far - and I loved doing them :3 It's for figure drawing - models are filmed doing 5 1-minute poses, 4 2-minute poses and 1 5-minute pose. It's really amazing for all of us who can't be a part of figure drawing IRL. It doesn't in any way substitute drawing from life (it's way easier to copy 2D into 2D than it is to convert 3D into 2D drawing), but it's better than nothing, right?

I know most of you don't draw humans, but anthro anatomy is mostly human, so practicing humans will improve your anthros a lot :)

I thought a practice tool as awesome as this one should be spread a bit... Go check it out and try it :3
https://www.youtube.com/user/onairvideo