OG peak
YYF 888 (only certain years though, some yo-yo people claim they can tell the difference. I’m still skeptical 
)
Monkeyfinger or RSO, but the earlier the model the more desirable.
Most A/RT yo-yos
Panorama
Diorama
Red blood cell
Any CLYW or One Drop to some extent, although the boomerness of the models increases exponentially as you go back to in time, especially for CLYW.
Anything that costs over $300, as long as it’s not made by Yoyofactory
Anything by Luftverk, except maybe the cheat code, because it’s it’s made for the DNA, which requires some learning, and is associated with TikTok.
Anything by a company that can be described as “boutique”
Anything described as “made in the USA”
Any fixed axle
Anything wood, as long as it’s not by Yoyofactory
Almost any slimline responsive, although less so if it’s made by a company like Yoyofactory.
I’ll add more if I can think of them…