I like Jasper Fforde's "Thursday Next" series, which consists of The Eyre Affair, Lost in a Good Book, The Well of Lost Plots, Something Rotten, and First Among Sequals. In the 1980s cloning has led to pet dodos and there are such things as vampires, time travel, and advertisements for toast. The main character, Thursday Next, is a detective who can send herself into books.
One of Turtledove's books I enjoyed was Ruled Britannia. It supposes that the 1588 Spanish attack of England had succeeded in imposing new monarchs and an Inquisition. Ten years later, William Shakespeare is given the task of writing a play meant to inspire a revolution.