stream. It was a request for Sweetie Belle as an anime/manga magical girl. Now a easy fall back answer would be the Sailor Moon style of outfit >> 1872757 s. However when I think of magical girls I often think of Cardcaptor Sakura. And not the hacked up American version.
In particular Sakura’s best friend Tomoyo Daidouji who designs her numerous “special outfits” for her friend to wear on missions. then Tomoyo recorded it later viewing. This outfit is based roughly off one wore in one of the opening credits. Link.