I use DXSC (forward, backward, strafe left, strafe right)
This means I get zaqwerfv keys for extra things. Thumb can alternate between alt and space.
*This* is the best config, since you hand comes in naturally from the right and is angled accordingly. With W and S at that angle, my hand would ache. Sometimes I rotate my keyboard counter-clockwise slightly for a bit more comfort.
To this day I've never seen anyone use anything similar.