Nothing fancy but fitting I think
Level 75 Reapers get Exclusive Sword & Hat maybe the one the Reaper Hideout Guy has. Plus Ominous Skeleton Symbols Curse
Level 75 Gold Hoarders
New Shovel? Maybe Upgraded Gold curse?
Level 75 Order of Souls
New Weapon Set made of Skeleton Bones. Skeleton Curse.
Level 75 Merchant
+1 To all inventory so 6 food, 6 wood planks, 6 everything, or 11 everything that was 10. Merchant Curse/ glowing hourglass & compass etc all over body.
Level 75 Hunters Call
Barnacle Curse!