Beau sounds great with 3-syllable mn.
Beau Atticus is fun yet stately.
Beau Emery and Beau Greyson are slightly predictable. I would prefer Emerson or Garrison.
Beau Rainer is my favorite with Atticus barely behind.
Beau Thomas is a bit blah unless it’s a family name. Honor names add ump!
I do like the alliteration of Beau Brooks (I like fn/mn alliteration and mn/ln alliteration but not fn/ln alliteration), but with both names being in the top 100 (in US), I’d do a less expected form like Beau Blaine, Beau Bryor, Beau Benson
I adore surname sounds with Beau, but I’m in South US where all surnames are game!
Beau Hemingway, Beau Attaway, Beau Anderson, Beau Ellison, Beau Emerson, Beau Gallagher, Beau Callahan, Beau Addison, Beau Leverett, Beau Sullivan
Classics I like with Beau:
Beau Nicolas, Beau Christopher, Beau Benjamin, Beau Jonathan, Beau Gregory, Beau Hamilton, Beau Harrison, Beau Zachary
Different-
Beau Jameson, Beau Riverton, Beau Donovan, Beau Branagan, Beau Tolliver
2-syllable I do like with it:
Beau Marshall, Beau Mercer, Beau Valor, Beau Dylan