I used some samples from Air Piano (https://www.pianobook.co.uk/library/air-piano) and I processed them with various plugins and techniques.

Convolution with weird impulse responses, distortions and tape simulators, reverbs and echoes with high feedback, granular processing, etc.

The result is a quite dark collection of pads and drones, nice for background and ambient duties but also to be layered with more bright, foreground instruments.

Ciao
Francesco