SearchKey and SearchKeyLite versions 1.4 are now Universal Apps, and should run native on all versions of macOS from El Capitan to Big Sur betas, on both Intel and Apple Silicon Macs.
SearchKey version 1.4 is now available from here: searchkey14
SearchKeyLite version 1.4 is now available from here: searchkeylite14
as well as from Downloads above, and from their Product Page, where you can also obtain full information about them.
If you experience any problems with either of these apps on an Intel Mac, I’m leaving their last Intel-only versions available from their Product Page.