Im suuuuper late to these but heres a couple sites and creators
https://www.hellolizziebee.com/where-how-to-buy-gyaru-brand/
This is a blog site from a gal
Some creators on tik tok would be @cinnagal @citrusmalicious @galdollz @walkingintrusiveth0ught @otknoharuka @dawlette_ @eggtok (egg magazines official tik tok) @lady._.lavender @regulxrr (mostly a cosplay acc doe)
Theres also always the gyaru wiki
and there was this one official gal site or smth but i lost it a while ago