This is looking great. One minor suggestion now that the Effect labels have been removed and the button icons are much smaller is to consider creating some new artwork for very common effects to harmonize them with well-known painting and image editing programs.
For example, the Draw tool could be made into a simple pencil icon, the Paint tool could just be a paintbrush, Flood Filling could be a paint can, Level Tracing could be a magic wand, Eraser just a simple eraser. I’m not sure what exactly to do with Scissors, the icon implies cutting/deleting to me, but the functionality is more like a “shapes” tool that lets you draw circles and rectangles. The more advanced, 3D image icons are probably fine as is, but worth putting some thought into given the new design.