Answer
As suggested on Kaylee Chatham’s comment, it is also called multiple selection listbox or multiple choice listbox.
As seen on number 6 in this confusing page I found, this could also be called an Accumulator:
Description: When a user needs to select items from separate sets of
search results or other large, unwieldy data sets- let them manipulate
the left (search, sort, navigate or filter), and add to the right.
Attribution
Source : Link , Question Author : Max Koretskyi , Answer Author : Luciano