I have a few that no matter what, when I find them, I "aquire" them.
Monogram 1926 Mack trucks. I have 6 of em.
AMT 57 Fords. 4 of them.
Revell 57 Fords. 3 of the station wagons.
Jordan Hiway miniatures 1/87 scale Mack trucks.. I cannot stop hoarding them. 6 built, 20 in the stash. ( actually, if you count the ones I built and sold, ... around 40.)
Tichy Trains 1/87 scale 22 foot ore cars. 12 built, 12 in the stash.
And, I can't pass an AMT model T without buying it . I'm not sure how many are squirreled away in the stash. 15 , maybe more.