Cool things to collect

Lalaloopsy

Polly pocket

Pinypon

Magic

Pokémon

Bandages

for the brave people there are various patches with different designs

Gachapon

I recommend “mercari” for this type of purchases

Books/mangas

Physical videogames

Stickers

Support your local artist if you can :D I always buy from them in conventions

Pins

Artbooks

Disney wishables

Disney pins

Squishmallows

Jellycat

Ty beanie babies