Learn English – the word for the metal things on boots where the laces go

The term is callus: (plural calluses)

• a hard and thickened area on the skin and especially on the hands or feet

(M-W)

Usage example:

• He was a migrant handyman with no calluses.

It's called an "aglet".

a metal or plastic tag or sheath at the end of a lace used for tying, as of a shoelace.

I've known and used this term for years but whether it can be considered "commonly known" is up for debate. It's certainly not unheard of.