Cardcaptor Sakura (1998)

Sakura was a normal fourth-grader until she stumbled upon the book of Clow Cards in her father's library. After accidentally setting the magical cards loose, it's now up to Sakura to catch them all again before they wreak havoc on the entire world! Luckily, she has her best friend Tomoyo, and Kerberos, the guardian of the cards, to help her. But when the help is more interested in costumes and video games than in Clow Cards, what's a young captor to do? And now Sakura has a rival, both in her chase for the Clow Cards and for the affections for her brother's friend Yukito....