Occasionally I still get asked about a 6 year old tool I made called Spritimator. This little .NET app allows you to import sprite sheets or individual textures and animate them then export the animations into XML data for your game engine as seen in this video:
Unfortunately I hadn't been supporting this app. However, in response to recent interest I got the app into a working state, fixing dependency issues, and providing a working binary via GitHub. Please feel free to try it out and I'll be around for some basic support :).