Ideas,
1: The Sabre battle above Reach and near Anchor 9
2: Halo 2 Scarab Battle
3: Halo 3 Hornet Battle at the end of The Covenant
4: Halo 1 Warthog Run
5: End of Halo 5's Argent Moon
6: Forward Unto Dawn Wreckage
7: Mombasa Streets
8: The Pelican above the broken Halo ring in the 2019 Halo Infinite E3 Trailer
Edit: I think mega saw this after learning they are making a pelican for infinite