Cardcaptor Sakura, Uta Kata Recommendations
Both are cute, magical animes about a young girl, and they both seem to get a new outfit almost every episode.
Uta Kata and Cardcaptor Sakura are two magical girl anime that feature a young schoolgirl given magic powers via a magical item. The main character actually doesn't have a fixed magical outfit, and is instead given a new outfit every time (well... almost in CCS's case) they use their magic. While both series are similar with these aspects and the inclusion of slice of life, it is worth noting that Uta Kata is darker than Cardcaptor Sakura.