NiceNamesOrg

Thanks for the suggestion. The potential problem with that is that it forces me to always use the same IP for https://nicenames.org because a lot of domains will be tied to that IP. I could use a CNAME, of course, but that's actually more complicated for the average user to set up than a straight forward (particularly because if you want to set up a CNAME for the naked domain (example.com), the way you do that differs from DNS provider to DNS provider (some places the feature is called ANAME, and some places it's called something different), and some don't offer that functionality at all.

Compared to that, forwards are very straight-forward (no pun intended) and are offered by virtually all registrars.

It’s significantly easier to list your domains for sale at https://nicenames.org. Sedo in particular is a fairly bad UI-wise.