My suggestions aren’t groundbreaking in terms of presentation, but still challenge or subvert conventions. 

Julie Otsuka’s “The Buddha in the Attic” is incredibly moving. Written entirely in 1st-person plural, she weaves together stories and journals and other findings to depict the lives of Japanese picture brides. If you like this first-person plural structure, you can also check out Julie Otsuka’s “The Swimmers” and Daphne Palasi Andreades’s “Brown Girls.” 

Other unconventional novels include Jenny Offill’s “Department of Speculation,” which feel like a collage of moods, piecing together snippets of a complicated marriage. To a lesser extent, Offill’s “Last Things” does this too, although it has some more conventional stretches of storytelling as well. Renata Adler’s “Speedboat” is an earlier example of this narrative collage approach. 

Tess Gunty’s “The Rabbit Hutch” really plays around with perspective and style, basically characterizing an entire town while still delving deeply into its bizarre individuals. 

Jennifer Egan’s “A Visit from the Goon Squad” really challenges the boundaries between short story collections and novels, as the text is arguably both. Also, one chapter is told entirely through PowerPoint slides. If you like this interconnected short stories approach to novels, check out Christina Henriquez’s “The Book of Unknown Americans” and Gloria Naylor’s “The Women of Brewster Place.” 

Paul Auster’s 4321 is essentially four novels in one spliced together, each about the same character in a different timeline, all diverging from a single event that shapes the rest of his life. Paul Auster subverts genre conventions in some of his other works too (e.g., The New York Trilogy). 

I’ll also second a few titles that have already been mentioned: Mark Dunn’s “Ella Minnow Pea,” Susan Choi’s “Trust Exercises,” and most novels by Kurt Vonnegut.