There's Lindsey Davis, who wrote the Roman mystery/crime/historical novels centring on private investigator Marcus Didius Falco and his far nobler, richer, girlfriend/wife Helena Justina. (Incidentally, Falco started out as an engaging loser living on his wits, fighting crime, and who was developing a drinking problem. He has an ambivalent relationship with down-to-earth pragmatic Emperor Vespasian and his two royal sons. While he despises the whole idea of Emperors and wishes the place were still a Republic, Falco is wise enough to treat the most powerful man in the Empire with at least minimal, but candid, courtesy. Vespasian in turn recognises his ability as a detective and sends him out on what might be called the less desirable Imperial jobs, to the punishment-posting corners of the Empire. Such as the wet hellish rainy cold swamp called Britain. Here, he meets independently-minded rich noble divorcee Helena Justina. Under her exasperated care, he gets better jobs. Helena's despairing family accomodate a son-in-law who would not be their first choice. She also serves to ease over those little misunderstandings that happen with the Emperor and others.
So far, so Sam and Sybil....
Lindsey Davis invented the term
tribute plagiarism and uses this shamelessly in conjunction with Terry Pratchett, incorporating many sly or hidden references in her works.
We at the L-Space Wiki have a whole page devoted to this, and indeed to other authors who have been similarly influenced by Terry,
here:-
http://wiki.lspace.org/mediawiki/index.php/Reverse_Annotations