Ableton Live allows you to have up to 12 return tracks; Send/Return Tracks A through L.
FAQ Tag: Sends and Returns
What is a send and return track in Ableton?
Ableton Live allows you to bus audio out from multiple tracks (say vocals, drums, lead synth, and pads) to a single track that has FX on it (for example reverb). This bussed track is only for FX. You can independently dial in how much volume from each track will be sent to this FX track. […]