I use lists on nostrudel for this. Would labels be better? 
I don't get the difference really. One is storing in a list and the other basically adding a tag. Both can be followed by others, with  both I can add one  event to multiple lists/labels. Is it computationally completely different maybe? 

The UX on nostrudel is freakin' great for lists (hat tip tonostr:npub1ye5ptcxfyyxl5vjvdjar2ua3f0hynkjzpx552mu5snj3qmx5pzjscpknpr ) so for now I'll use that 😉