Sound it! Series
Internet Co. have released Version 8.4.3 for their updater and installer that are compatible with macOS Big Sur (Intel/Apple Silicon) for Sound it! 8 Pro and Basic.
Already installed Sound it! can be updated with using InActivateCenter. When you need to re-install Sound it!, you can get the new installer from the Download Center.
VST/AU Plugins
Current F-REX and MSEQComp plugin software are compatible with Big Sur(INTEL/Apple Silicon).
VOCALOID Libraries
Still under the testings.