Well lets run over all the games that would be compatible
Minerware has minimum PvP so it doesn’t really need to be added
Tower defence has no PvP
All arcade games except barn brawl would be either incompatible due to things like elytras in wing rush or aren’t fighting based
But even barn brawl wouldn’t be relevant since the only PvP in it involves knocking players back
Archer assault isn’t a melee combat based game
Bingo has no PvP
Lobby games have no PvP
Skywars and eggwars are already 1.8
Duels has a 1.8 mode and FFA does too
Freebuild obviously no PvP
Even if parkour was released no PvP
Lucky islands has numerous drops that only work in 1.9+ along with blessed mode requires the luck effect and that was added in 1.9 not to mention the texture pack is for 1.9+
So be completely honest with yourself for a second
Do you really want SG, Blockwars, infection, and/or UHC?