>>9889436I think they resemble Capuchins, which would make sense as they're prominent in pop culture and easily tamed.
https://en.wikipedia.org/wiki/Capuchin_monkeyThey are too big to be Capuchins though, which may just be Lego's abstract scale. The closest New World monkey to the Lego monkey's size is the Woolly Spider Monkey.
https://en.wikipedia.org/wiki/Muriqui