Oede

The oede is a type of reed that grows in marshes. The milk flowing through its stalks is reputed to "push the limits of life" as herbalists say.
Drinking a vial of oede infusion grants a +1 bonus to death saving throws for the next minute. This bonus is to be considered as the raw result of the die, meaning it's impossible to roll 1 and a 19 on the d20 becomes a natural 20.