1) If I had all-boy triplets, I might name them
Jack,
Riley and
Blake.
2)
Jack is my top name so if the boys weren't triplets I would probably still use it. However, as individual names,
Jack,
Riley and
Blake are fairly common, I feel the fact they are triplets would set them apart enough. If they weren't triplets, I might be inspired to name
Jack's brothers something less common, e.g.
Jack, Bellamy and
Bridger - if they were singleton brothers, I also wouldn't mind so much about 2 beginning with the same initial.
3)
Tate,
Quinn and
Kaden. [surnames]
Riley,
Quinn and
Kaden. [Irish]
Bellamy,
Cassidy and
Tennyson. [outside the Top1000 in England & USA]
Jack, Stark and
Blake. [same ending sound]
Jack,
Kade and
Finn. [1 syllable]
Phoenix,
Riley and
Sidney. [unisex]
4) Bellamy,
Bridger and
Blake. OR
Sebastian,
Sidney and Stark. OR
Tennyson,
Tobias and
Tate.
https://www.behindthename.com/pnl/117870?sort=gender&pop=ewTop ~
Juliet (g) and
Alice (g)
Bottom ~
Harper (g),
Peyton (g) and
Kade (b)