Om next is still in alpha and changing rapidly, so some of the following links may be out of date. A good resource to keep up with current developments is to sign up with the Clojurians Slack Channel, channel #om.
Fulcro - A library for building full-stack SPAs. Provides a lot of the "glue code" needed in Om Next, including initial state helpers, reduction in the need for parser code, and a simple but full-featured load system. It also has commercial users. (fork of Untangled, which is no longer maintained)