The Ben Aaronovitch series Rivers Of London is fantastic - a Cop who can do Magic.
Amazon.co.uk User Recommendation
Robert Rankin (Someone else mentioned him) is very funny, as is Tom Holt
https://www.bookseriesinorder.com/robert-rankin/
https://www.bookseriesinorder.com/tom-holt/
A couple of oddball ones, that I think have not been mentioned - Edward Marston (The Railway Detective series: 16 in total, with a 17th due out in the Autumn / The Home Front Detective series: 8 in total / The Bow Street Rivals series: 4 in total). Railway Detective is set during the Victorian era. The Home Front Detective series is set during World War One, and the Bow Street Rivals series is set around the turn of the 19th century.
Andrew Cartmel - The Vinyl Detective series. Set in modern times, they're about a guy who can be hired to find rare vinyl records, but gets into all sorts of trouble along the way (Written in Dead Wax/The Run-Out Groove/Victory Disc/Flip Back).