I'd definitely agree with the people recommending Robert Rankin.

Tom Sharpe is also funny (Wilt, Porterhouse Blue, etc.)

Also (disclaimer that it's by someone I used to know which may affect my judgement) Go Up by Simon Broadbent is clearly influenced by the Terry Pratchett books set in Ankh Morpork.

I didn't like it quite as much, and it is more middle grade, but A Wizard's Guide to Defensive Baking feels kind of Pratchett influenced.

I recently read The Stranger Times by Caimh McDonnell, an urban fantasy about a tabloid reporting on supernatural events that's very tongue in cheek and although the humour doesn't always hit, it did remind me of Rivers of London by ways of Terry Pratchett. The characters are certainly very Pratchett-ian. The story starts of with the Stranger Times looking for a "new Tina" a.k.a. assistent editor because the editor is insufferably rude and terrible to people. The job description reads: "Publication seeks desperate human being with capability to form sentences, using the English language. No imbeciles, optimists or Simons need apply."

I don't know you, but I love you already 💖

Neil Gaiman - More on the Fantasy side than irony. His works are still a pleasure. And ofk his collaboration with Terry "Good Omen". Also check "American Gods" and "Anansi Boys".

Kurt Vonnegut - Not what you would call "Fun and laugh" works, but his stories are crazy, well written and full of irony and smart social critics.