I was frankly surprised at how much more often rare loot drops with a potion of discovery.
Potion of discovery are additive.
0,1% x 110% = 0,11%. That's a 10% increase
0,1% + 10% = 10,1% That is a 10000% increase.
Somehow these discovery boosts work additive on the special drops from chests.
In saltmarsh it is VERY noticeable with the sentient xp and the fragments. With the anniversary djinn boost even nebula fragments were dropping.
Those 2 weeks i got like 60k sentient xp with a few sagas with a discovery pot and the djinn boost combined.