Chronological order: Magic Knight Rayearth, Card Captor Sakura, Angelic Layer, Tsubasa: Reservoir Chronicle, xxxHolic,
Code Geass? (maybe not)
All of which I've seen/watched only as anime.
Watched Magic Knight Rayearth as a very young child. Seen the OVA at a different channel after years of absence. Don't remember much about it now except that they're 3 color coded schoolgirls (blue, red, and green. Wait a minute... PPG?) from the real world summoned to another world by some long haired blonde princess person (or is it that white wizard guy?) and they were each given magical talking giant mech-like knight armor things that has the same color scheme as they do.
xxxHolic looked a bit bizarre to me due to its "noodle people" design. Haven't saw anything like this in anime before. Liked the mystical and weird events going on in their. Some have those life lessons moral in them. Some give you bits of insights into some of Japanese culture/legends and other topics related to magic, fortune telling, etc. Gives you the feeling that you're actually learning something rather than watching another "magic show".
Tsubasa: Reservoir Chronicle's characters look surprisingly like the main characters of Card Captor Sakura. They even have the same names. First (and only) time I saw one of this kind in anime.
I've read somewhere that these anime/manga is some how connected to each other. Something about the black haired witch lady from that show and the Clow Reed person I've heard so much about in Card Captor Sakura (and occasionally in this one and xxxHolic) traveling to dimensions or something.
Angelic Layer. Interesting concept with the whole "battle doll" idea.
Must be inspired by those robot combat matches and anime figurines.
Also there's Card Captor Sakura. An odd combination of tarot cards, wizardry, ghostbusters-ish (except they're not ghosts), and magical girl (also thanks to the costumes Tamoyo she made her wear).