Lich

The moniker Lich could refer to one of multiple vehicles employed by the Covenant and its remnants:
*Type-56 "Lich" GS/UHDP - An aerial vehicle employed by Jul 'Mdama's Covenant and the Swords of Sanghelios in Halo 4, Halo 2: Anniversary and Halo 5: Guardians.
**Banished Lich - A variant of Lich employed by the Banished, and featured in Halo Wars 2.