There is a place on GitHub for a Self wiki:
People can add implementations there.
Great idea! Seeing the list of projects reminded me that my own projects only ran on older versions of Self. It would be nice to update them to fix this.
Wasn't there another Self in Java at one point? dSelf or something like that?
Indeed, and searching for that found it mentioned on one of my own pages :-)
dSelf is described in the paper "dSelf - A Distributed SELF" by Robert Tolksdorf and Kai Knubben from 2001:
A quick search didn't turn up anything about OpenSelf. The mailing list archives might have something about that.
Marvin, announced in 2005, was supposed to be a Self implemented in Squeak by Pavel Krivanek, but I can't find anything about it beyond its SqueakMap page:
One interesting thing about both zigself and PySelf (for want of a name :) is that they both seek to define a small subset of the Self distribution as a core - booleans, collections, strings, etc.
Early versions of Self were basically just the core stuff. Unfortunately the earliest copy I have on my machine is Self 3.0 which already had 185 .sm files (Self module, I suppose?). I do have Self 1.1 but in a tape that I can't read.