HCE:
Indoor, and Ruined Pain
H2:
Anchor Point, Raceday, Untitled Blastacular map, Earth City, Beach Battle, and covenant_sample.
H3:
Gauntlet, Monkey Mountain, Warthog Inc, and The Lost City.
H4:
Breaking Point, Deadlock, Blood Pit, CA Ching, Forerunner City, Dish, Escalation, CA_Gorge, Remnant, Station, Fortress, NoLoad Tower, Pillars, Island, Sinkhole, Extinct, CA_Constant_Strife, CA_Peanut, CA_Shipyard, CA_Standoff, DLC_Junkyard_Craneswing, Arrowhead, Covenant underwater technology, Genessis, Last Resort remake, Narrows remake, ONI Bog, Sandtrap, Z06_pillars, Z07_island, Z08_experimental alongside maps Z02, Z03 and Z04.
Halo Online maps for H3:
Drydock, Lockout, Powerhouse remake, Sky bridge, Reactor, Diamondback
Halo Online maps for H3:ODST FF:
Beachhead
These would be cool if they were restored.