1. Death Island
2. Danger Canyon
These were all only Halo PC maps so they're basically new maps to most Halo players. Most peeps probably won't mention them. Plus they're awesome. Death Island and Infinity are excellent maps for team vehicle convoys of Warthogs and Ghosts. And Banshee escort!
Your team can spawn and load up into 3 warthogs, 2 ghosts, 1 banshee, 1 Scorpion (A wraith may be better nowadays), then roll out in force! Such a fun vehicle map as it was massive and you can choose between several routes to avoid foot soldiers/snipers/fuel rod spawn or maybe a pesky Banshee patrol.
You could also do insane jumps from the top section of the island - drive off the edge for like 5 seconds of airtime, onto the beach to avoid a banshee or enemy. I've killed warthog players in mid air with the banshee bomb lol. Was so much fun to do.