I had triplets on my very first TS4 family. The couple just got a girl and I was like "Let's get her a sibling" and then the game was like "Oh you want siblings? Well you get three trololo!"
Not gonna lie, it was pretty aggravating to have 4 babies at once all crying in a loop but at least the parents gained parenting skill like woah and I actually really enjoyed the challenge when they were toddlers.
The triplet boys are called Abel, Blaze and River. I think those are all in-game names cuz I was curious (and lazy) so I just rolled that dice to see their offerings.