Only bit of “EU” that didn’t rely on the WEG game that I can think of is probably splinter of the mind’s eye.
You’re forgetting The Han Solo Adventures by Brian Daley, The Lando Calrissian Adventures by L. Neil Smith, and the Star Wars/Droids/Ewoks comics published by Marvel. 😛
I’m pretty sure that the Brian Daley novels were still considered canon in the 90’s. I have a PDF copy of a WEG book called “Han Solo and the Corporate Sector Sourcebook” from 1993. The Corporate Sector was almost exclusively in the Han Solo Adventures.
Also according to Wookieepedia most of the Marvel comics still counts as canon, although with a few tweaks here and there. Which suits me fine, as some of the early Marvel content is surprisingly good.
I really wish Wookieepedia had a pre-PT “Legends” section. It’s hard to keep track of all the old WEG Sourcebooks, and the Galaxy Guide books are mostly just over-glorified SW dictionaries.