PvP addon highlights nameplate of your group’s most targeted enemy player with a red cornered box. Target caller can use the addon to prioritize their target with priority target icon, and get visual feedback on group’s targeting with top target icon. Non target callers in heat of battle can use the addon to target same target. Potentially a massive advantage.
Get addon: https://www.curseforge.com/wow/addons/toptarget
Requires enemy player nameplates enabled in World of Warcraft settings: Interface > Game > Names.
(Video mistakenly says both friendly and enemy nameplates required, but only enemy nameplates are required in this version.)