A list of ES6 feature lists

• “ECMAScript 6 Features” by Luke Hoban
• “Learn ES2015: a detailed overview of ECMAScript 6 features” (Babel docs)
• “ECMAScript 6 Cheatsheet” by Erik Moeller
• “First steps with ECMAScript 6” by Axel Rauschmayer

Complementary and indispensable: “ECMAScript 6 compatibility table” by kangax.