Lots of things. The main one is dust mites. Any clothes that I have in my closet or drawers that I haven’t worn for a while will make me sneeze uncontrollably for an hour if I pick them up. Same if I get a spare sheet from the linen closet, if it’s been in there for months, it will set me off. When I vacuum the house, I need to use one of those hypoallergenic HEPA vacuum filters. Dust mites are everywhere all the time, no matter how well you clean your house. Technically it is the shedded and disintegrated shells of dead dust mites that people are allergic to, it accumulates over time in places the mites live.

Other than that, I’m also quite badly allergic to black mold, and have a reaction to pollen and grass seeds.

I’ve never taken a proper allergy test, I’ve probably got others I don’t even know about.