Many other guest vocalists recorded sessions during the duo's post-"100th Window" era but are not featured on the album, including: Stephanie Dosen, Yolanda Quartey of Phantom Limb – effectively Robot Club's band) and Jhelisa (Anderson, who had previously recorded in 2002 in the studio for material that was not included on "100th Window"); and, mostly during the pre-"Collected" time – Mike Patton, Aku and Akwetey Orraca-Tetteh and Devang Shah of Dragons of Zynth, Elizabeth Fraser, Terry Callier, Fredo Viola, Debbie Clare, Beth Orton and Dot Allison. Mos Def and Leslie Feist were named as artists scheduled for recording sessions back in 2004. Backing tracks from Grant Marshall's side of Massive Attack's writing (mainly facilitated by and done with Robot Club) are known to have been sent to Alice Russell, and prepared for Sharon Jones, Patti Smith and David Bowie during the era but collaboration did not come to fruition, nor did talks with Tom Waits or Tricky, in terms of featuring as guest vocalists on the record. Post-punks Mark Stewart and Keith Levene were pictured inside Del Naja's 100 Suns studio in 2009, but played no part on the album.