In my case I think it was the Kaladrax reborn min from Bones 1 - which if I remember right apparently came out bigger than Reaper had expected due to some confusion or miscommunication with the factory in China on dimensions! I do remember for definite it was massive, and far beyond what I'd...
Sold that one as well. Realised once it arrived a) quite how massively out of scale it was with my existing Pirate ships (Blood and Plunder models) and b) that the box was so big it was a struggle to actually store (and absolutely zero chance of hiding or denying its existence and purchase to...
I ended up selling mine, after it had sat in the box for a while judging me, when I finally realised I hadn't got the time (or inclination) to actually paint it, or the space to store it or display it once fully assembled :(
After AD&D (1st, PHB then DMG; MM came later and somebody else had one to tide us over) came Traveller (the deluxe boxed set including LBB 0-3, Adventure 0, Starchart of the Spinward Marches, and dice - £10 back in the day!)
Zozer Games make some very nice Cepheus Engine books - link to the main Universal (2d6) rulebook below.
https://www.lulu.com/shop/paul-elliott/cepheus-universal-hardback/hardcover/product-844v94n.html?q=zozer&page=1&pageSize=4
I only wish my adverts were even tangentially related to gaming/D&D, my family use my Amazon membership so I get ads tailored to what they are currently buying and streamimg :D