A simple mod which highlights your party members with a tag. Inspired by @codename-B's Facepixel. It proves that example mods can contain some useful functionality as well!
Forge: 188.8.131.522 for Minecraft 1.8.9.
Download the binary (1.2.1) from maxkorlaar.com/download and put it in your .minecraft/mods folder. (Re)start your game and you should be good to go!