What words have plurals formed by adding -en?

The words that form their plurals by adding "-en" are quite few, and are mostly archaic or specialized:

* Ox: oxen

* Child: children

Note:

* The word "brethren" is an archaic plural of "brother", and while it is still occasionally used, it's considered somewhat formal or religious.

* The word "kine" is a rare archaic plural of "cow".

It's important to note that while "ox" and "child" form their plural by adding "-en," they are irregular plurals and don't follow the standard -s/-es pluralization pattern.