by Klaus Hoffmann-Hoock

1990 "Fragrance" by Software (supply of synthesized sounds)
1991 "Ghost of a Mist" by Ron Boots (guitar on "Desert Clouds")
1992 "Live – by Popular Demand" by M.O.R.E. (guitar on "Unitas Special")
1993 "Virtual reality" by Patrick Kosmos (co-composer of "Monolith")
1993 "Different Stories and Twisted Tales" by Ron Boots (guitar on "The Call")
1994 "Let There Be More Light" by Peter Mergener (guitar on "Wildlife")
1995 "The House of S. Phrenia" by Solar Project (sitar and voice on "Religion's Fire")
1995 "Schwingungen-Club presents New Instrumental Music" (sampler featuring "Rohan Rider")
1998 "Traces of the Past" by Stephen Parsick (co-writing, guitar and Mellotron on "Submerging",
"Close beneath the Surface", "Cosmic Jellyfish" and "Quicksilver Sea", remix of "Green Depth")
1998 "Nodular" by RAMP (remix and final mix)
1998 "Silence the River" by Hans-Werner Faßbender (remix and final mix)
1998 "Rot" by Menschenfisher (Mellotron on "Dort in Süden" and "Zu Feige zu Leben")
1999 "Joie de Vivre – Live Again" by M.O.R.E. (guitar on "Aftermath")
2000 "Fish 'n Love" by Pyramid Peak (guitar on title track)
2000 "Heartbeat by Hans-Werner Fassbender & Klaus Hoffmann-Hoock
2001 "Five" by Solar Project (sitar and voice)
2003 "Psychedelic Breakfast" by Klaus Hoffmann-Hoock & friends
2003 "Analog Overdose 3" by Schönwälder & Fanger (guitar)
2004 "Space is everywhere" by Harald Nies (mix & samples on "Surreal India")
2004 "Ayurveda Buddha Lounge Vol.4" (electric sitar on "Stargazer")
2005 "Time Traveller" by Roger Matura (Mellotron)
2005 "Parlez-vous électronique?" by Thomas Fanger (electric sitar, guitar,samples)
2005 "Oughtibridge" by 'Ramp (live recording)
2006 "Vision of Asia" by Peter Mergener & Klaus Hoffmann-Hoock
2007 "Conundrum" by Klaus Hoffmann-Hoock & Bernhard Wöstheinrich
2008 "Etherische Chemie" by Rivercrest (Memotron, electric sitar)
2009 "Follow me down to Chesil Bay" by Roger Matura (electric sitar on "La nuit et la mer")
2012 "Ian Boddy, Klaus Hoffmann-Hoock & David Wright" (Live at Electronic-Circus 2009 - DVD)
2013 "Earshot" by Fanger, Schönwälder feat. Cosmic Hoffmann (electric guitar, Memotron, soundmix)