I have found a huge tunings collection of 5100 scl scale tunings which can be imported into openmpt, they can be found at https://www.huygens-fokker.org/docs/scales.zip (https://www.huygens-fokker.org/docs/scales.zip) also see https://www.huygens-fokker.org/scala/downloads.html#scales (https://www.huygens-fokker.org/scala/downloads.html#scales)
You can view the contents here https://www.huygens-fokker.org/docs/scalesdir.txt (https://www.huygens-fokker.org/docs/scalesdir.txt)
That collection is why we support scl import in the first place ;)