All of the classic rigs have been freshly updated to support Autodesk Maya 2017-2020, with a select few supporting back to Maya 2012. They all feature real-time playback through Maya 2020’s cached playback on modern workstations. Most characters hit real-time through standard parallel evaluation as well.
They are listed from newest to oldest — the newer the rig, the higher the quality and value you can expect. See product pages for more details.