I've never quarantined snails or shrimp. That said, they (especially the shrimp) require a proper acclimation period. At least 2 hours using a drip.
I doubt too many people are set up for quarantining corals, considering the lighting requirements. Yeah there are guys with big fish rooms with multiple frag tanks, grow out tanks, and all that. But I really doubt the average person quarantines corals.
Fish for sure though.