Junk Era sets are an easy one here, but I will go another direction with the ones I've seen.
Unlicensed modern Panini baseball cards have dramatically fewer folks wanting them. It's really pronounced in the early Panini sets (2010-2015) where only a handful of folks have insert sets on their wantlist. With recent sets released, it's not as pronounced, but still significant. I ran the data on 2021 Topps Chrome versus 2021 Panini Prizm, as they are competing products in a similar family.
2021 Topps Chrome base set has folks with 6246 cards on their wantlist
2021 Panini Prizm base set has folks with 3201 cards on their wantlist
It's easy to understand, most people want the logos! But if you are looking for mass appeal trade bait on modern cards, licensed cards is generally the way to go to get more trade partners.