I would like to present to you my newly built editor MapComplete.
MapComplete started out as a tool to be simple to use for one
specific topic, namely nature. Users could
select a piece of forest, nature reserve or park and answer
questions about it; or they could add one of those themselves.
I set it up from the start to support multiple themes (a bit like
MapContrib), and there are already quite a few themes available
now (namely aeds,
and a few more).
But OSM wouldn't be OSM if that would have been enough. By now,
there is a page available where one can
create their own theme. If you have over 500 changesets, you
can create a theme from scratch which can be shared via URL. The
customgenerator is still very unpolished but should be usable.
Development happens on github. If
you notice an issue or have an idea, make sure to open an
issue. There are still a ton of bugs out there, and help on
translations and more themes is definitively welcome!