DriveThruRpg.com is having a big sale on D&D stuff which finishes tomorrow. Its all pdfs, but its a good chance to check stuff out for a very very low price since titles are discounted up to 40%.
D101 Games has a selection on the sale, and Crypts and Things is 40% off.
There’s also a number of Brtish OldSchool Renaissance (BOSR)on sale
The Midderlands, Monkey Blood Publications fantasy take on medieval Britain, with the expansions is listed.
Cthulhu Hack 1st ed. Not specifically a version or even a take on D&D, I suspect this is listed because its derived from the The Black Hack. A new edition is incoming, but I’d still recommend it.
Scott Malthouse’s take on fantasy British folklore, published by Osprey Games, is also in the sale
If you re after old UK TSR stuff, that’s all in the sale.
Personal recommends from this long list, U1 The Sinister Secret of Saltmarsh (1e), Fiend Folio, UK2 The Sentinel (1e) and its sequel UK3 The Gauntlet (1e), and UK 6 All that Glitters (an all time favourite of mine).