Thirst is a simple mod that adds a thirst mechanic to the game, but that fits well in modpacks (especially aesthetics-oriented ones) by adding diverse features and compatibility with a lot of often-used mods.
This mod is heavily inspired by the other thirst/survival mods out there, including Dehydration, Tough as Nails, and Cold Sweat.
To learn more about this mod, you can visit the Wiki.