I have killed rahabkor over 100 times now and I looted 1 bellicose wings with a mythic sea shell.
I've encountered 2 people who looted a shredder aura, some who got bellicose wings, 1 who looted a heroic egg, 1 mythic egg, a legendary 81 belt, and a deep sea vanity vest war.
What have you guys looted and what have you seen others loot? How many estimated runs have you done? Here are 2 vids of around 50-80 of my runs if you are interested.
Full hp bosses 3x speed random runs: https://www.youtube.com/watch?v=LUZgDcni4rI

1% hp boss kill clips party + random runs: https://www.youtube.com/watch?v=cytmZqqlpFE

Rahabkor guide + solo: https://www.youtube.com/watch?v=c8U2YW0Fp5E