I've been on a late-night hunt for free read-aloud books more times than I can count, and honestly, the internet is a treasure trove if you know where to look.
Start with LibriVox — it's basically the go-to for public-domain audiobooks read by volunteers. You'll find classics like 'Pride and Prejudice' and 'The Adventures of Sherlock Holmes' narrated in a wild variety of styles; some readers are theatrical, others calm and steady. Pair LibriVox with Project Gutenberg for text copies if you want to follow along. The Internet Archive is another goldmine: full audiobooks, radio readings, and even old public radio recordings. Loyal Books (formerly Books Should Be Free) aggregates public-domain audiobooks too and gives a nice, easy interface for browsing by genre.
For younger listeners, Storynory and Storyline Online are brilliant — Storynory offers original and classic tales, while Storyline Online features actors reading picture books (their video readings are great for bedtime). Lit2Go from the University of South Florida is an underrated educational resource with downloadable MP3s and accompanying PDFs. Don't forget library apps: Libby/OverDrive and Hoopla let you borrow professional audiobooks for free with a library card, often including modern reads.
Pro tip: check copyright status before downloading, use podcast apps to follow serialized readings, and try speed controls to match your listening pace. I love mixing a LibriVox classic after dinner with a LeVar Burton episode on tougher days — total comfort combo.