Think old dusty upright pianos or electric pianos (Rhodes/Wurlitzer) drowned in bit-crushing and delay. These are used for chord progressions. They ground the ethereal synths in a familiar, organic feeling.
While stock presets are great, the secret to the "Plugg scene" is custom sound design. The Roland user marketplace has exploded with creators specializing in . Here are the top banks to look for (and Google): zenology pluggnb presets