I may add an atlas sometime soon, just haven't had the time in the day to make it. I've been pretty busy and unfortunately at the moment I'm actually sick :(
Once I'm better though, I can take another look.
As for the palette, I actually do have a palette I use! It's just very large lol. If you want a palette to select colors from, the palette I use is the Google UI palette on Aseprite. For lighter tones, I'll generally take the base color and shift it towards yellow, and for darker tones towards purple. Hope this helps!