Well, since Michael's death, I've heard that Lenny Kravitz, Akon, Will.I.Am, Rodney Jerkins, R Kelly, and The-Ron (music producer).
Lenny said that he has a completed duet with Michael from the Invincible sessions. He said the song was about Michael's life and was triumphant.
Akon has worked a lot with Michael, but it sounds like they didn't really get to final productions on their songs. But hoping that there is something that could be salvaged and put together by Akon.
Will said that they had recorded a lot of dance tracks together. But he also said that Michael kept his vocals and Will kept the music because Michael was afraid of anything leaking. There is also that song about James Brown that they were working on together after James died.
Rodney says that he has 9 completed songs from the Invincible sessions that were amazing. I heard there are a lot of completed tracks from the Invincible sessions that were put aside.
R Kelly said that he has about 5 songs that they had been working together prior to Michael's death and that they are not completed. I don't know if Michael put any vocals down for him though. I hope so! Kellz says that he is going to finish them.
The_Ron says that he worked with Michael last year in Vegas and they worked on a lot of unreleased songs and they are all sitting in his hard drive.