Hellobee Boards

We use cloth napkins at home. I have cotton ones from Target (and I think I have picked up some from HomeGoods, etc. over the years); they're about 12"x12" and they have held up reasonably well to regular use and washing. I also pack my lunches with them, and find them very useful.

These look similar to what I have, though I usually just stock up whenever I see some on the clearance shelf:
https://www.target.com/p/4pk-cotton-easy-care-napkins-threshold/-/A-82261007?preselect=79568015#lnk=sametab

ETA: Actually, I just measured one of ours, and it is 18"x18". That sounds large, but I don't perceive them as big (we have other, larger ones that I don't like as much for everyday use). My five-year-old uses these daily (and has been since she graduated from the highchair) without any trouble. I fold them into eighths for the table or packing, which makes them a fairly standard napkin size, and I would say 90% of the time, she just keeps them folded and uses them like that.

We have the same target ones as @ladybaltimore and my 3.5 year old uses them fine. I actually originally got small ones and her teacher said they were too small to practice folding with