I've recently upgraded from FF57 to Quantum (since the add-ons' Big Glitch) and New Tab Tools is a great replacement to SuperStart on which I relied on heavily.

In future developments however, would it be possible to group several tiles in one "file", as well as have the option of a "blank tile" that one could use as a separator between tiles.

Finally, useful tip for the dummies like me: If you want New Tab Tools as your Homepage, just drag the add-on icon in the address bar over the Homepage icon... et voilà!

Thanks again and keep up the good work!