
Quick answer — Kaori Shimizu voices Lain Iwakura in Serial Experiments Lain, Signum in Magical Girl Lyrical Nanoha A's, Akira Takano in School Rumble and 20 more characters.
Kaori Shimizu voices Lain Iwakura (Serial Experiments Lain), Signum (Magical Girl Lyrical Nanoha A's), Akira Takano (School Rumble), Noriko Nijou (Maria Watches Over Us: Printemps), Kumi Kawamura (Alien Nine), Nonoha Itou (Phi Brain: Puzzle of God), Kei Ueshima (Kamisama Kiss), Seri Mizutani (Hell Girl: Two Mirrors) and 15 more.
Lain Iwakura is voiced in Japanese by Kaori Shimizu.