What to do when you've hit a plateau in a rainbow?

[FTLFTL]

First, this title sounds like an allegory, but it's not.

I decided to see how many of a specific card I could get and got every single one that's /50 or more common except for two, but I can't find them. Like, when do you give up? Any thoughts as to how to find one, short of emailing every single LCS in the NY Metro area?

(If you're wondering, the answer is the 2024 Lindor Topps, 650 paper and 137 chrome.)