Collectable characters are usually cute little figures they sell well due to people wanting to collect as many of them as possible. You can also remake them in other ways, like trading cards or key chains. Collectables I found were labubus, pokemon cards and Lego mini figures, all of which have different series' available.

Dice towers are something everyone needs (if you play TTRPGS (Table-Top Role-Playing Games) like Dungeons and Dragons. They're used to role your dice by putting it in a hole, and it will fall or slide out and role for you. They come in all shapes and sizes, for example a magic tower, a goblet or a castle dice tower. There are many possibilities. 

Pencil toppers and key chains are popular smaller items and could be offered as a cheaper option.   

People also like customisable options, most of these things could be customised with people's name or initials.