Yeah after watching triple threat show it got me thinking about some artists doing some songs or some projects together. I know you must have thought about it too but here i would just list five of my head ;

1) Drake, J.Cole & Kendrick Lamar
I have thought about this several times i can't even think exactly how it be like but there are just too many options and scenarios. But it would just be amazing , the kind of lines they would spit the things they would describe it would just be too on point.

2) Chris Brown & Drake
Though the have some issues they make really nice music individually and genres and styles are not to far off. I think collaborating would not be a bad idea at all (except if they fight or something)

3) B.O.J & Jesse Jagz
I'm really into that Alternative vibe that they both have and BOJ would probably kill the hook and the production would be really heavy. Most likely they would deliver a classic chilling jam.

4)  Adele, Jhene Aiko & Taylor Swift
This would be the most emotional breakup song it would just too epic. I can only imagine the vocal performance it would be awesome, probably with some acoustic instruments they would leave niggas sobbing and what not(on some cry me a river stuff)

5) Beyonce, Eminem & Nas
 All i can say is that it would be Legend... (wait for it) ...