Brand and era make a difference.

Many makers matched the Campagnolo choice, (save the mid 80's on self extracting bolts/caps) but I don't think you are inquiring about those.

TA and Stronglight both had unique sizes as did their crank arm removers.

I forget what Nervar used.

There were some variations as to internal profile shape to clear the bolt or spindle/nut.

Personally, I just go the way I did as a young racer copying what the pros did, no dust caps. I do keep them but probably have fewer pairs than I have bikes. I am surprised often at the handsome sums that are paid for some on ebay. $24. for a pair of red plastic Sugino units!?