Here’s a few suggestions for improving the handy canvas toolbar.
It’s great to have some settings at easy reach but I’m missing some and the ones there can be made clearer. Now they are designed to take as little space as possible.
If we group them into different popups with an icon each the UI can be cleaner, the toolbar shorter and we can add more features at the same time.
can be grouped into one popup but are often changed so it can be useful to keep them as is (at least for me)
 Low resolution
 Show grid
 Snap to grid
 Show guides (much more useful than grid to me but not currently present in toolbar)
 Snap to guides
 use onion skins
Past onion skins 
Future onion skins 
Add a canvas properties icon
Render and preview icons
keep as is.