AMS files are multi-cycle waveforms that can be generated from Ableton Operator's additive synthesis editor. It can also be used with Ableton Sampler and Simpler.
Waveforms for Ableton Live
Updated July 28, 2019
AMS file - [2274 ams files + 12 Presets](Live Pack)
Presets are created using simpler, so they can be used by any Ableton Live user.