Watch the Robust online guitar lesson by TrueFire from Play Acoustic Guitar 6: Lick Vocabulary
Robust - Trick 31 is a video guitar lesson presented by Matthieu Brandt and is sourced from 50 Chord Tricks You MUST Know.
Another cool way of playing chords is to not play all the chord notes at the same time, but play them sequentially. When you leave an open bass note ringing, your ear will add up all the sounds it hears to a 'chord' it can make heads and tails of.
This chord trick uses sets of sixth intervals on top of a pedal bass.