These are the Soul Collectors spots. There are 6 spots to find.
Bottom Floor Spawn Room https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=972605261
Middle of Map where Speed is https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=972605297
Near Stamin Up https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=972605332
Near Jugg where Box spawns https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=972605370
In Front of Widows Wine Behind Power Room https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=972605413
At Pack a Punch in front of Mule Kick https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=972605453
Rewards can be (so far what I got)
Minigun
Weapons (NV4, UMP45, HBRa3 so far I got)
Free Perk (Only way to get Eletric Cherry for free without using gum)