Over the past 30 years I have worked with many musicians. In areas covering development, services, recording and live mixing.
Here follows an alphabetical list with no guarantee for completeness.

Andreas "Schrader" Dorn ● Ali Neander (Rodgau Monotones) ● Axel Heilecker  Blind Guardian Bömmel (Bläck Fööss) Bosstime Brian May "Breiti" & Andreas v. Holst "Kuddel" (Toten Hosen)  Bruno Müller (Mezzoforte)  Carl Carlton Carlos Perón (YELLO) ● Carlos Santana Chicken Devine Creator ● Clode Bonifaz  Department of Rock Dieter RoesbergDirk Mies, Peter Nika (Jokebox) Ebi (der persische Udo Jürgens)Elton John Band  Emily G  Guildo Horn Gunther Gabriel  Helmut Kaiser (Music Store)Helmut Krumminga (BAP) Helmuth Zerlett Ina Deter  Jakob Hansonis (Herbert Grönemeyer) Jens Raffelsiefen (YouWho) ● Jens Ruthenbeck (MLMSC)Joe Cocker Band Jörg Fischer (Accept) ● Jörg Hamers (Popolskis) Jukebox Heroes Klaus Bittner Klaus Heuser Klaus Spangenberg  Laith al Deen ● Lorenz & die Band Marc Metzger Markus Winstroer  Mayqueen ● Oliver Schwung ●  Queen Kings ● Paul Mc Cartney Band ● Paveier ● Peter Fischer (AMA Verlag) ● Peter Maffay ● Pink Cream 69 ● Pit Hupperten (Allerwertesten, Herbert Grönemyer, Sarah Conner) ● Rainer Heide (Einzahn) ● Rammstein ● Raymond Linden ● Richie Samborra (Bon Jovi) ● Robby Mildenberger ● Schuller  ● Sinner ● Steve Lukather (Toto) ● Steve Stevens ● The King ● Tohjo ● Thorsten Schmitz (Schlecht) ● Thomas Blug ● UDO ● Udo Klinkhammer ● Uli Stöveken (Real Guitars) ● Uwe Bossert (Reamon) ● Westernhagen ● Wolf Hoffmann (Accept) ● Wolf Maahn ● Wolfgang Niedecken ● Wolfgang Petry ● Zeltinger ● 12 Drummers Drummig u.v.m.

Service for studios, publishing companies, organisations:
EMI ElektrolaDierks Studios StommelnStudio N KölnCoconut StudiosConny Plank StudioMusik Media Verlag (Gitarre & Bass)Green Peace (Traileraufnahmen)

 

Of course I'm bounded to the local scene in the cologne area for years:

Bierbörse Opladen  Jazztage LEV Streetlife Leverkusen Topos Leverkusen u.v.m.