I didn't know that was a producer tag, either, but I love them and think they're funny. I'll start with some that I like or I think are particularly iconic:

• "Mustard on that beat, ho"
• "And if the beat live, you know Lil Ju made it" (I can't think of this one without immediately then hearing in my head "hands on my knees shaking ass on my thot shit")
• Obviously "WE THE BEST MUSIC...DJ KHALED"

Here are some that I didn't know were producer tags or couldn't figure out until recently:

• "Daytrip took it to 10" (could tell it was clearly a producer tag, but had no idea what he was saying til a friend sounded it out recently)
• "Listen to this track, bitch" (I just thought these were the words to the song lmfao)

Underrated ones:

• "Jetson made another one"