
Quick answer — Mami Kosuge voices Izumi Sakurai in Nichijou - My Ordinary Life, Yukari Takara in Lucky☆Star, Satori Magiru in Student Council's Discretion and 6 more characters.
Mami Kosuge voices Izumi Sakurai (Nichijou - My Ordinary Life), Yukari Takara (Lucky☆Star), Satori Magiru (Student Council's Discretion), Kureha Tsuwabuki (Kaze no Stigma), Motoko Kouzuki (Rumbling Hearts), Kelly Wong (Black Blood Brothers), Aya (Omamori Himari), Touka Kurenai (Grenadier: The Beautiful Warrior) and 1 more.
Izumi Sakurai is voiced in Japanese by Mami Kosuge.