The 3 biggest winners of the sets to go EOL in the last 12 months have been GE, HH, and TH. After this, you have Mixels (and before you SSD me, that set hasn't doubled in value; all the previous one have. Only TH arguably meets the "rarity" criteria, but certainly not "rarity" by CC or GG standards, and GE and HH violate both your rules, as most certainly do Mixel Series 1, they were everywhere and wholly invented inside the Lego Universe. I think there's a completely different dynamic, and that's collectability, set design, and perceived appeal. If a design is particularly appealing or good + that set is part of a collected series or theme, that's the recipe for doing "quite well" IMHO. Exhibit A: Modulars. Or, to be a bit more broad, basically any Lego exclusive.