I started this site/playground decades ago. Originally, because I wanted a searchable database for D&D 3E monsters, but it's fun to program new stuff, so I kept adding stuff. Mostly for 3.5E.
I don't devote much time to this site so many tools are rough on the edges. The 5E spells database is still rudimentary, for example.
And many of the graphic generators are too "square", but they're the most fun to write.
Recently I've adopted Traveller (mixed with Cepheus Engine) and realized I could reuse a lot of the code already in there and made a first attempt to make a Subsector generator and later a table calculating Interplanetary travel times.
~~Which leads me to this shameless plug: If you're interested on a Traveller RPG community, please drop a comment on this post I created at !community_meta@ttrpg.network.~~
Edit: Alas, I ended up creating !scifi@ttrpg.network instead.