In BASIC land, the QB64pe project has a maintainer for Inform-pe, a pretty straightforward drag & drop interface builder:
https://qb64phoenix.com/forum/showthread.php?tid=1311
Here's an example running under QB64 (though not Phoenix Edition/pe):
https://www.youtube.com/watch?v=a9pNGBaIr94
Background on the Phoenix Edition:
https://qb64phoenix.com/forum/showthread.php?tid=259
There's also Purebasic and Gambas, though Gambas isn't cross-platform...
https://gambas.sourceforge.net/en/main.html
Zooming further out you have e.g. Defold and Cerberus X, which I'm not sure about the drag & drop but GUIs are certainly doable.
https://www.cerberus-x.com/community/index.php?pages/about/
Then there are Wonkey and wxBasic...
https://wonkey-coders.github.io/
Et cetera... :-)
Personally I'm pretty fascinated by the way these projects typically center around a traditional forum, with various software structures in place that shape the user experience.
For example, prolific library authors may be invited to publish directly to their own subforum and kind of use it as their own website, etc.
When new projects start, spin off, fork, etc, the forum is often the first part of the user experience to see created, frameworked and decorated in depth.