Here’s what r/javascript had to say:

• React.js with Flux (a view-only library and an eventing module)
• Ember.js (a full MVC framework)
• Knockout.js (view-only library)
• Backbone.js (full MVC framework)
• Meteor (full isomorphic framework)
• Mithril (full MVC framework)
• Ember (full MVC framework)
• ‘No framework; just lots of libraries’
• Vue.js (view-only library)
• Breeze.js (model-only library)
• Ractive (view-only library)