You're asking in the classics forum, so I assume you're interested in older books. Anything in Keith Laumer's Retief series, about the adventures of a galactic diplomat, might be a good choice. Very broad satire, if I remember them correctly.
Another classical humorous SF novel is The Witches of Karres, by James H. Schmitz. I used to love that one, but it might be a little dated now. The humor might be described as witty and gentle, rather than broad and freewheeling.
For SF with fantasy trappings (Earthman lands on medieval-type planet with witches, wizards, and fairies etc., but it all comes down to psi powers), there's Stasheff's The Warlock in Spite of Himself and King Kobold. After that, I feel the series went downhill, as Stasheff continued to mine the same territory over and over and over. However, the first two books were a lot of fun, and the series, begun in the late sixties, I think, continues to this day, so somebody must still be getting a kick out of it.