Oooof. I sold off my PS3/360 collection as well in 2011, but I used the money to re-purchase Steam versions of my favorites. I also had probably half as many as you've got there. Do you regret any specific titles in particular?
I mean, Alice, Puppeteer, Siren Blood Curse, both God of War Collection and Yakuza Dead Souls are probably worth what the guy paid for the entire thing so yeah I regret these one. They're not hard to find, just pricey now.
The one I regret the most is not here and is even more crazy:
I lived in Viet Nam for 11 years and used to order from Play-Asia all the time during the PS3 and 3DS era. I didn't really collect at the time, just buying games i wanted to play. Play-Asia often had sales and free shipping for Viet Nam.
One day, i bought this:
I was really interested about this game so I got it but didn't even open it. A few weeks later, I moved to another apartment and sold a bunch of stuff before moving, my PS3 and the games I had included. Probably got around 200 bucks for the lot.
This game has become one of the rarest and most expensive game to get on PS3 if you're looking for the version with the English subtitles, people ask over 500 for it. There's a cheaper Japanese only version and I believe a Korean version that also have English subs but this one is also several hundred to get.
So yeah, wish I still had this gem.