5. Dying Light: Bad Blood
Four words: Battle Royale with zombies.
One of the many existing franchises to bolt a battle royale mode on, the sheer quality of Techland's last major expansion, Dying Light: The Following, should give you a lot of hope.
Techland are already taking registrations for Bad Blood's standalone multiplayer add-on, which sounds like a cross between The Division's Dark Zone and a miniature Battle Royale - with some neat twists. The mode is based on just five players dropping into a zone infested with zombies, yet they must scavenge to survive, fighting enemies and each other - but not too quickly, as the only way to beat larger bosses and survive at all, is to work together first.
Also factoring in is an evacuation chopper with a limited number of seats; spaces that can only be paid for with huge numbers of "samples" acquired from dead enemies. These are paid per player, and the only way to get enough samples is to work as a team first, letting the totals rise - before back-stabbing your nearest comrade and hoping you can make it out.
At some point you're going to need to be a turncoat, but when that happens is up to you... or those around you.