Cassie has posted some songs on her youtube channel, which were never recorded or officially released. They are listed under here, with a link (if this is still available) to the songs itself. 

Some songs may have been released in the past, but are no longer available. 

Cassie wrote the song around the same time as her debut album, but it never made it onto the album. The song became available for free on robnsteal.biz. However, since that site is no longer in the air, the song is no longer available from there. 

New Moon (twilight sequal) was happening and Cassie wrote this song to be a contender for the soundtrack. Too bad it was never chosen. The song was released, but is now nowhere to be found. Luckily we ripped the video before it was taken down.

Although it is not entirely clear when this was written, but it was posted on a youtube channel in 2009 after hearing it in a Degrassi game. The song was never released and this is the only recording of the song I've ever heard/found.

Cassie posted this song, written and performed along with Mike Lobel on her youtube channel.  The song was available for sale around Christmas, but it is no longer available.

A song Cassie wrote in 2010, while she was dating Jarrett. She performed it with Mike Lobel, and the song is still available on her youtube channel.