Following up on "Bro!", I've discovered a useful coinage from Canada: Matthew Urichuk and Verónica Loureiro-Rodríguez, "Brocatives: Self-reported use of masculine nominal vocatives in Manitoba (Canada)." In It’s not all about you: New perspectives on address research,  2019:

This study focuses on nominal vocatives that have been traditionally associated with male speakers and addressees (familiarizers in Leech’s terminology, 1999), and which we will call ‘brocatives’.

And that reminds me of the Dude discussion in LLOG a couple of decades ago:

"Dude, 12/8/2004
"Dude, no way", 12/9/2004
"Duding out", 12/10/2004
"Dude unbound", 10/9/2010
"'Dude'", 11/12/2010

Those posts referenced Scott Kiesling's 2004 American Speech paper "Dude", recently reprised in Scott Kiesling and Soobin Choi, "Disenregistering dude: Shifts in familiarizing vocative meaning and use in American English." In Sociolinguistic Approaches to Lexical Variation in English, 2025.