For those asking (quite a few pages back) about playable Grung - they are (sort of) available already. (info
here)
The death curse is in effect within Chult. If you die, you cannot be resurrected. The only way to get your character back is to enlist a surrogate from the ones proved here on the WoTC website (don't know if this info is also in the book).
One of those surrogates is a Grung Rogue (available at Tier 1 and Tier 2)
Not sure how many will actually use it though as it has this mechanic:
WATER DEPENDENCY.
If you fail to immerse yourself in water for at least 1 hour during a day, you suffer one level of exhaustion at the end of
that day. You can only recover from this exhaustion through magic or by immersing yourself in water for at least 1
hour.