You could check sold listings on
ebay to see what Fanattik are selling for. If these are mostly copper/bronze metal pieces, silver or gold plated etc. they likely won't appreciate a lot in value IMO. Just because something is marketed as limited edition does not mean people will want them or they'll be more valuable in the future. These are not coins, not legal tender, they are a collectable. I assume Fanattik products appeal to kids, teenagers, adults who like Sci-fi such as Lord of the Rings, Harry Potter, etc.
Private companies and private mints contract with movie studios and the like to license products. Niue Mint for example has the rights to Star Wars characters. Tulavu Mint has the Marvel characters, Spider Man, etc. These are gold and silver, not copper/bronze. There's some YouTubers who collect, buy/sell themed gold/silver rounds.
Some enjoy collecting tokens, medals, etc. but I don't know much about it. If you like collecting stuff like Fanattik, sports cards, comic books, coins, whatever, enjoy the hobby. Just know what you are collecting, their current prices, some may increase in value, some won't.