This release lifts the requirement for running under the dnd5e system. It should work generally on item, macro and active effect sheets. I haven't tested other systems. Let me know if it works or if it doesn't.
You can now use custom icons. Place them in a directory called icon-pickereither under the world directory (to only have them available in the given world) and/or under the Foundry data directory to have them available in all worlds where the module is active. There is also a hook called icon-picker.build-roots for use with supplementary modules or world scripts.