The most pernicious scams focused on English-speaking writers these days come from overseas: publishing/marketing/fake literary agency scams from the Philippines, and ghostwriting/editing/marketing scams from Pakistan and India.
That's not to say there aren't plenty of scammers in the USA, Canada, UK, and Australia. And scams aren't all you need to watch out for: inexperienced literary agents (aka schmagents) and incompetent publishers can also hijack your work and create major problems for you. Right now, though, overseas scams are the ones you're most likely to encounter, and they are the most predatory.
An increasingly frequent fraudulent tactic, used primarily by the Philippine scammers, is impersonation: of reputable literary agents, major publishers, renowned movie production companies, even bookstores and organizations like the American Booksellers Association. The aim is to convince you that you're on the cusp of real, reputable representation, publication, immortality on the silver screen, books on shelves nationwide...there's just something you have to pay for first (a screenplay, a "cinematic trailer", an IP lawyer to handle contracts, "book licensing", a "book returnability program"...the list is endless). Once the scammer gets you on board, it's open season on your bank account: you will be heavily pressured to spend more and yet more money on goods and services that may be hugely overpriced, entirely fictional, never actually delivered, or all three.