From Halopedia, the Halo wiki
Banshee Raider • Baron 'Sraom • Captain Wamik • Covert Major • Duelist Hunter • Elite Prime • Elite Ultra • Ghost Jockey • Ghost Marauder • Goblin • Hunter Elder • Pilot 'Dalamen • Platoon Captain • Patrol Leader • Ranger Commander • Remnant Hunter • Sangheili General • Sangheili Pathfinder •
Captain Hestro • Commander Lochagos • Commander Malice • Endurance-of-Will • Hydra Soldier • Knight Bannerman • Knight Champion • Knight Dignitary • Knight Excavator • Knight Luminary • Knight Marshal • Knight Noble • Knight Strategos • Lord Viratus • Phaeton Helmsman •
This is a template that lists boss enemies in Halo 5: Guardians Warzone.