[Red Badger]

The 10mm wrench is always missing.................

[Yo-Yo]

Harbor Freight had you in mind when they created this item:

https://www.harborfreight.com/10mm-metric-essential-socket-set-10-piece-58957.html

The PITTSBURGH® 10mm Essential Socket Set comes with a full range of standard, deep, flex, and impact sockets in drive sizes 1/4 in., 3/8 in., and 1/2 in. This socket set is ideal for replacing lost 10mm sockets or filling out a master mechanic's tool set.

[Conan the Librarian]

Those who might wish for a 10mm may actually GET one....

Personally, I think they don’t exist.

[mowowie]

No kidding...