Marcus Wynne's latest novel in his revengers series, Jeff, is being published via Kindle Vella (see here). It is a serial format so that a section will be published periodically. Marcus talks a bit more about it his blog post, "Hey Friends, Show Kindle Vella Some Love Will You?" Although Amazon started the service, it hasn't done much to promote it, according to Marcus. I can say that although I have purchased all of the preceding books in the series, I haven't seen anything I recall pointing me to this new book. Anyway, check it out--you can read the first four sections for free, and then after that you purchased tokens that allow you to read subsequent pieces.