Campbell lettered on and off as a hobby until he realised he was getting paid as much for his lettering as for his day job, around his 40th birthday.
- Inspectre (written with Kev Walker (Megazine 3.23 - Megazine 3.33)
- Hoax Hunters
- Vampire Vixens of the Wehrmacht
- Department of Monsterology (by Gordon Rennie and PJ Holden)
- Violent! (Action tribute fanzine, 1999)
- Dæmonifuge (writer with Kev Walker for Games Workshop's Black Library)
- Superior Charity Special