Easily create your own asset variations using simple to use software! · By Kenney
Here you can share any custom templates you've made, simply place the .ken (and optionally the .png file) in the /assets/ folder or anywhere on your PC and use the "Load from file..." option.
Power-up template (by Gee It Some Laldy)
It would be awesome if you could batch-edit tiles, so an entire tileset would change color instead of having to change each one individually.