Making a drawing software is hard and takes a lot of time. I think I will take a break from programming Shadowforge until I don't know when honestly. But things I have planned are (note: these are only plans):
Balanced and Unbalanced Opacity Brush.
A fast rectangle from start mouse point to end mouse point, that can copy things on the surface faster than what is used now.
Things that are very far but still planned: Free hand lasso tool (I'm uncertain if GML can do this and copy the mask to the docker). As far as I know, it can only copy X and Y and the Width and Height. When it copies this to the docker, the whole Width and Height is copied but not what was masked to be copied.