expressions - What would be an English equivalent for the Mexican Spanish word tocayo?

In Mexican Spanish (not sure if other Spanish speaking countries use the word too) we call "tocayo" to those people that share the same name as us (but not necessarily the same last name i.e., Juan Gonzalez and Juan Carlos Castillo are tocayos).

I was wondering if an equivalent for this word exists at all in English or maybe even an expression?

Answer

People who share your name (whether full name or just part of it) are your namesakes:

A person or thing that has the same name as another

As Hot Licks points out in the comments, namesake is most commonly used for someone or something that is intentionally named after you, but it can be used for non-intentional, coincidental name identity as well. The Wikipedia article has a brief discussion about whether a namesake is necessarily named after its, erm, namesake—starting out with the following:

Namesake is a term used to characterize a person, place, thing, quality, action, state, or idea that has the same, or a similar, name to another—especially (but not exclusively) if the person or thing is actually named after, rather than merely sharing the name of another.

The OED article on namesake has quite a few citations using the word. In many of them, it’s quite hard to tell from the snippet whether the namesakeness is coincidental or intentional; but a few are definitely coincidental:

The Beacon … was nicknamed ‘the State Fair apple’ and was for years sold at its namesake event. (Minnesota Monthly, 1995)

I enclose a letter for your funny namesake and kinsman. (Croker Papers, 1826)

So even though it is most common to use the word for someone or something that is intentionally namesaked after someone or something else, it is legitimate and historically precedented to use it to refer to more coincidental namesakenesses, too.