Attached Link: True Bones: Game Pack

If you've a budget, True Bones has a huge selection of BVH. One in particular is called Game Bones. It has more than 200  short motion capture which I think would be perfect for your 2d Sprites. The good thing about his site is you can buy them one at a time and he usually will offer you a good deal once you purchase anything from him. I bought 1 BVH, just to test them and he gave me half dozen to play around with and offered me his entire catalog of about 2,500 motion captures for $99US.

There is also www.es3d.com which sells Poser animations that are fairly high quality.

If you're short on cash, I recommend www.mocapdata.com. That sire has a lot of free motion capture that can be easily imported into Poser. Lastly, if you're still looking, the entire Carngie Melon motion capture is available in BVH format. (www.sharecg.com/pf/full_uploads.php). They often require a lot of work, but can't beat the price.

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