Wish I would have kept the a cheap snub nose 22short pistol my Grandpa gave me when I was 11 I traded it to my aunt for my great grandpas .32 he carried in military.
My wife had a Beretta Cheetah Model 84 in .380 acp...which we traded for her Glock 26 after the birth of our first child! That is the only gun I wish I had back! It had a great feel to it, shot great, and handled every type of .380 acp ammo that we ever fed through it without a hiccup! It would be nice to have to teach our daughter (age 7 now) to shoot semi-auto. Great little gun!
Colt Python .357 4 inch blue from their custom shop, Colt Gold Cup .45 acp series 70, 1903A3 Springfield 30-06 that had the left side of the receiver milled out to use the Pederson device. A pre 64 Winchester 30-30 made in 1956, S & W model 19-2 2 1/2 inch pinned barrel and recessed chambers.
This may sound silly but I had an old savage 22 over 20 that I sold that I would REALLY like to get back. It wasn't real practical, but it was fun. On a side note, sellers remorse taught me since that I don't ever sell a gun that I have purchased. Since that time I have bought many...and sold none. I'm much happier now, even though I get a "why do you need so many" question from the wife from time to time.
Let's see... just about all of them. We'll start with the two M1A's, Ruger Security Six, Colt pre-Series 70 National Match, High Standard Supermatic Citation, S&W Model 41, the consecutively numbered Ruger Mark II factory overrun KMK512B's... I can't continue, this is killing me.
I wish I could have all of them back but instead of using them un-lawfully to get money I had to sell most of them to keep a roof over my familys head and to keep there bellys full