genuinely great shouts for the guitarist by the vocalist

Not on record but a live memory - Glastonbury 1979, an 'all star' jam with Alex Harvey and Steve Hillage and I forget who else; they're doing Small Axe -the Marley song - and after the second chorus El Vambo goes 'Take it away Steve' - minutes turn into apparent hours........ eventually Alex, thinkly Glaswegian ' Bring it back Steve'

"thickly"

"Rub it on me, Duane!" -- Jesus Lizard, "Nub"

On "Super Bad," it's: "Blow me some Trane, brother!"

Gram Parsons's shoutout to James Burton in 'Cash on the Barrelhead' is a classic of this genre. it's funny how on one level he's introducing James to his (patently fake) live audience, but on another level he's bragging to his actual audience about how lucky he was to have gotten the great James Burton to play on his record.

I'm not sure if I'll ever figure out exactly what he's saying, though. "James Burton and his hot ẗ̸̰͉̹́̿'̵̱̣̅͠ç̵̿ͅḫ̵̭̯̈̆'̵̦̀͐j̶̖̾̓'̵̢͛̚͝r̵̨̉̂ả̸͈͙̕i̵̡͔̓̕ṇ̴̟̽g̸̭̩̟͑l̴̙̅i̶̫̱͒͊n̵̘̜̈̈́g̴̨͇̼̏̌̐ guitar"???

"Judah Bauer, step up to the stand!" Jon Spencer, JSBX - Attack

Latinamerican people surely recall this one:

“Echale vampiro”

The opening shoutout on Mana’s “Me Vale” which is one of their biggest stadium anthems.

Not a song I love but It’s the most popular shoutout I can think of.

As Bob Dylan and Johnny Cash stumble through their Nashville session (Bootleg Series v. 15), Cash repeatedly shouts out Carl Perkins, not so much to incite Carl, it would seem, as to make sure listeners know who's playing guitar

C'MON JAMES! from Lulu obv

Was gonna mention two, then I found I already mentioned BOTH! TWELVE YEARS AGO!

No mention of "guitar hero!" from U2 at Red Rocks?

'genuinely great'

I dunno, I think the singer making fun of his guitarist on a live album is pretty great.

ha

A less cheeky one is Neil Young's "Speakin' Out." "Alright Nils, alright," goes Neil, right before Nils's (second) masterful guitar solo.

“C’mon Steve, get it!”

This is right before Steve’s (first) masterful guitar solo.

Steven Tyler screams "Look at this, Brad!" as he falls offstage

"Judah Bauer, step up to the stand!" Jon Spencer, JSBX - Attack

― Deflatormouse

This is actually the most substantial lyric in the entire song.

"Give us some wah-wah, Dirty!" on the Cosmic Psychos' "Custom Credit".

"C'mon Steve!" from Def Lep's Armageddon It

^this is the one that comes immediately to my mind.