One of the many cools things Nicholas added to SmallBASIC years ago was the concept of "modules".

A module is a separate .dll (or .so) file to provide specialised programmable functionality similar to the unit concept.

Unfortunately units and modules never really took off for SmallBASIC, but maybe this will change.

I recently came across a very nice looking graphics API called Nuklear, - be sure to scroll down to the screenshots.

This wouldn't be a good fit to include directly into SmallBASIC but it seems perfect as a module. I've started working on something just for fun. Here's an example program that is already working:

There's nothing ready to download yet, maybe in a couple of weeks. The moving parts will be: command line version of SB plus one or more DLL files.