Hello! I just released my first tool on itch!
https://george-bailey.itch.io/sprite-slicer
The tool is a Automatic sprite slicer that can do single files or hundreds of files in seconds supporting multiple image formats with a few additional features such as
Background removal with Tolerance
Color Reducer controls for Sprite sheet or individual sprite slices
Duplication filter with tolerance for likeness
Minimum size slices it will do, avoiding artifacts and stray pixels.
I can't claim it's perfect just yet, but with a bit of love and feedback I'm sure it can get better :)

