What's the name of this addon?

[Atlowz]

The one he uses to show every health bar with animated icons

https://www.youtube.com/watch?v=_Yrpo4EbNRo&t=143s

[skullatbash]

The one he uses to show every health bar with animated icons
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I am not sure which one do you mean.

The one on left side is party frame of "XPerl"
The one on right side is "Gladius" (which is an Addon for Arena)

If you mean the "debuff icons" above enemy's head is "PlateBuffs" addon instead. (the healthbar above their heads is just the Blizzard "nameplates" )