They won't release a list of participating breweries, but all of the California, Colorado and Washington mainstays are expected to be there: Lost Coast, Anderson Valley, Lagunitas, Sierra Nevada, 50/50, New Belgium, Tahoe Mountain, Golden Road, North Coast, The Bruery, Anchor, and more.
If you can, make this a long weekend and stay in Lake Tahoe for a few days. Rent a boat or paddleboard, do some hiking in the Sierra Nevadas, and enjoy swimming in the clear, icy water. You can easily take the local bus routes to and from Foam Fest, or simply call an Uber (please don't drive).
If you start looking now you'll find great places to stay at a decent price; rustic ski cabins on AirBnB, ski lodges and hotels on Priceline, Kayak and similar sites. But don't wait too long, Foam Fest takes place Labor Day Weekend, and prices will go up fast.