Nas- Hip Hop Is Dead
Going into that album, there was so much promise. He had just signed with Def Jam, did the Scratch magazine cover with DJ Premier, and squashed the beef with Jay Z. There was the joint interviews with he and Jay and another one with Nas and Rakim. There were reports of him working with Premo and him getting production from Dre, Kanye, and Just Blaze. Then Nas did an interview with Rollingstone and previewed some songs ("Hip Hop Is Dead" and "White Man's Paper" featuring Damian Marley). He said he had/wanted production from Dre, Scott Storch, Timbaland, Pharrell, and will.i.am. Album drops and there's some bangers, but it ends up being an underwhelming Nas album. He had another Scratch cover with him Game, and Will.i.am. In the interview Nas said he had 5 other songs (produced by will.i.am that he was saving for his next album that were better than anything on HHID. Aside from "Ghetto", the rest never came out.
Nas- 2014 Album
Nas reportedly was working on an album produced by Timbaland, Swizz, and No I.D. Nas described what he did with Timbaland as "powerful". They even did a song titled "Sinatra In The Sands". Large Professor recently called what he heard "crazy". None of the music has seen the light of day aside from a 15 second snippet Timbaland posted in 2015.
OutKast- The Hard 10
Initially, this was 10 songs entirely produced by Organized Noize to commemorate OutKast's 10 years since dropping their debut. Never saw the light of day.