Can be from any genre. Mine is when an acoustic guitar comes in towards the end of a song and totally changes or reframes the mood/energy (see "Money" by Widowspeak)
I like it when the vocalist announces what's coming next, like yelling "GUITAR!" right before a guitar solo or "bring back the horns" right before the brass section kicks in or "sing it, girls" right before the female backups echo the refrain.
I really like this one for certain genres like Funk or RnB that are generally more energetic and spontaneous when performed live. Helps the recorded material feel a little more alive.