Collectables need some good temperature control, no exceptions
Toys can be collectables, but collectables are never toys, does that make sense at all? Anything that has real value can be a collectable, be it a book, a comic, a toy, a game, or a glass from when McDonalds gave away things made of glass (probably before your time), however but if you buy an action figure, for example, and then unaffix it from the package to play with it appreciate a toy, then it is no longer a collectable, but collectable items sold on the secondhand market need to be mint condition, still in the original packaging, and never having been played with, to help keep them in the best condition I command using a dedicated Heating, Ventilation & A/C proposal for your collection, of course you need to have a private area, a sealed room for example, and it should have its own temperature control proposal in locale; In the worst case scenario you can use the central Heating, Ventilation & A/C proposal for your house, but even then I guess you need an additional dehumidifier for the collection room to get rid of that extra moisture, then nothing ruins a collectable — any kind of collectable — more than moisture, so a dehumidifier is worth its weight in gold to a extreme collector.
Of course if they are out of the packaging it doesn’t matter if they get moisture destruction, so whatever, but if they are in the box then don’t scrimp on the dehumidifier.
I was fortunate enough to build a collection room in my basement, where the walls supply temperature moderation I just need to use a dehumidifier not an Heating, Ventilation & A/C system.