So, this is exactly what it sounds like. Humble Bundle is offering a book bundle from Night Shade Books featuring books from a variety of genres ranging from sci-fi to horror to fantasy to maybe even a little mystery. Included are a few “best-of” short story collections as well as a number of longer novels. I’m not personally familiar with a lot of the authors, although there is a collection of Paolo Bacigalupi short stories. They claim the featured authors include names like George R. R. Martin, Neil Gaiman, Jane Yolen, and Orson Scott Card–I’m guessing in the short story collections. The full-length novels are mostly by authors I don’t recognize, but i looks like an interesting group of books.
If you’re interested, you can find this bundle at https://www.humblebundle.com/books/multi-genre-fiction-books.