The IsometriX engine has a demo of a walking figure. You might be able to use its sprites for your test.
http://www.mygale.org/hatti/MrY/isoxeng.html

Does anyone know a site with some pictures of sprites that I could use just to test my engine? What I'd need is a character which has a walking animation in at least the eight directions of up, down, left and right and the combinations. A few additional actions such as walking with a secondary animation, such as a weapon in hand, and swinging the weapon wouldn't hurt.

The ideal case of course would be a collection of different kinds of creatures, buildings and terrain features, but even a single character would suffice

I've got some tiles that looks ok and I think they're free to use too, but I only use them as test tiles.
It's about 150-200 tiles good quality bitmaps.

Send me a mail to netz@home.se if you want me to send them. (They're 1.9 MB but I can make them jpg ify you preffer that)