What are some of your guys favorite collaborations between two artists?

Mine:

Andre Nickatina & Equipto - Midnight Machine Gun Rhymes and Alibis

A-Wax and Woodie - 2 Sides of the Game

Criminalz Starring Spice 1 & Celly Cel – Criminal Activity

San Quinn & Messy Marv - Explosive Mode

Rydah J Klyde & Lil Tae - Flexin & Finessin

Messy Marv & San Quinn - Explosive Mode 1 & 2