A total of 26 sites are hosted on 172.217.21.46.
Here are the first 5 as they would appear when searched for:
youtube.com/user/johngifu
(null)
youtube.com/user/VzAebatista
(null)
youtube.com/user/beautifullybellaify
(null)
youtube.com/user/thehebihebi
(null)
youtube.com/user/amyleethirty3
(null)
...and the list of the remaining 21:
youtube.com/user/YRFTrailers
youtube.com/user/CorridaNoAr
youtube.com/user/deportesavela
youtube.com/user/matsku84
youtube.com/user/Armani
youtube.com/user/aloeblacc
youtube.com/user/OurFamilyWorld
youtube.com/user/akemikenta
youtube.com/user/LovelyBabyMusic
youtube.com/user/pasha4mmm
youtube.com/user/serjonew
youtube.com/user/PCprostoTV
youtube.com/user/rustamnazipov
youtube.com/user/vcsabiavideos
youtube.com/user/martinbonari
youtube.com/user/BOOTCAMPMC
youtube.com/user/liltranscriber
youtube.com/user/SugarCharmShop