Conversation so far:
What did Ai Otsuka do in 2006?
In April 2006, Ai Otsuka released Frienger. The promotional video was used as the commercial song for the Toshiba W41T 4 GB MP3 mobile phone.
Where was the video for Frienger by Ai Otsuka shot?
The promotional video for Frienger was shot in Taiwan.
Was Ai Otsuka an actress and a singer?
In June 2005, Ai Otsuka made her acting debut with the drama Tokyo Friends.

Question: What singles did she release?
Self-contained rewrite: What singles did Ai Otsuka release?