I think it's neat that there's so much merchandise, but a lot of it is stuff I won't ever buy. Keychains, pillow covers, tiles (???), and a whole bunch of other useless items...
I highly prefer plushes and figurines. I am very picky with those and only have a few things; for instance I only get my favourite characters and things I know I'll like 100%, otherwise I regret the purchase very soon. The only pieces of merch I have are a Saber figurine from Fate/Hollow Ataraxia, a big plush from Monomi from Dangan Ronpa, and a Master Ball plush (not really anime merch but w/e). I have a few posters from magazines and a few Weiss Schwarz cards (which I only have as merch and not as playcards), and I am looking for specific ones.
I do kinda sideye people who buy very sexualised figurines; I find them tasteless.