As mentioned Aseprite has a linux build.
Pixelorama is very similar to Aseprite, but has free builds. Is built with Godot and is open source.
It looks like Aseprite can export a texture atlas, but I haven't seen the ability to do so in Pixelorama.
For lighting effects there's an application called Sprite Lamp (also has a linux build) that's been around for a long time. I haven't used this one though.
I haven't done any of these workflows in awhile but I hope that this helps.