I like center-pinch lens caps as they try to hold themselves on. I don't bother with the leashes, they get in my way. I just buy more caps when I lose them.
I lose a lot of them. Sometimes I wonder if there is a section of the Pacific gyre dedicated to my missing lens caps.
The link is for 52mm caps, but you can adjust the size on the Amazon page and buy whichever you're currently losing. The only lens cap I've held on to (thus far) is the weirdly unique one for my Nikon 14-24 F2.8