Tomb Raider: Definitive Edition

This can be boosted in a private match, simply load the map beach go the turret in the middle of the map and kill your boosting partner 20 times with the mounted turret and the achievement is yours. You can boost all MP achievements in private match, but the achievements for ranked wins must be in the online ranked playlist

Can be boosted on Beach or Underground. The quickest way we found to do it is with a session of 4 (2 players per team). Alternate turret kills between one player on each team. The reason for switching players each kill is that it allows the killed player to still spawn on their teammate. This method works well because it allows for other players to make progress on their 20 turret kills during the time players are waiting 10 seconds to respawn.