Oneshot-Control
A lightweigth minecraft mod aimed at configuring max damage to avoid oneshots.
This mod allows you to configure how much percent hp a player or entity can loose max in one hit. Basically you set how many hits are needed to die, which allows a bit more counterplay opportunities than getting oneshotted. Works great together with mods which make/add more difficult enemies, as it smoothes the scaling of those.
The mod is only required on the serverside, but may be freely installed on either side. Feel free to use it in any modpack.