Here is all of the Convar halo commands:

fmod_halo 1 or 0 (set this to 0 for no halo) what it does: Enable halo effect that will appear on the following NPC'S

fmod_halocolor_r (0 or 1) What it does: it sets the halo for the following NPC'S red.

fmod_halocolor_g 200 (set this to a higher or lower number i think) What it does: it sets the halo for the following NPC'S green.

fmod_halocolor_b (0 or 1) What it does: it sets the halo for the following NPC'S blue.

fmod_chat_support (1 or 0) What it does: "Enable additional informations in chat."

Welp thats all of them, i seen people say (how do i disable the halo?) so i looked in the .lua file and found you can indeed disable it, but yeah enjoy.