Download recent releases

softwareupdate --fetch-full-installer --full-installer-version 10.15

Version can be taken from the list below.

$ softwareupdate --list-full-installers
Finding available software
Software Update found the following full installers:
* Title: macOS Sonoma, Version: 14.5, Size: 13353373KiB, Build: 23F79, Deferred: NO
* Title: macOS Sonoma, Version: 14.4.1, Size: 13298513KiB, Build: 23E224, Deferred: NO
* Title: macOS Sonoma, Version: 14.4, Size: 13297753KiB, Build: 23E214, Deferred: NO
* Title: macOS Sonoma, Version: 14.3.1, Size: 13073278KiB, Build: 23D60, Deferred: NO
* Title: macOS Ventura, Version: 13.6.7, Size: 11924125KiB, Build: 22G720, Deferred: NO
* Title: macOS Ventura, Version: 13.6.6, Size: 11917983KiB, Build: 22G630, Deferred: NO
* Title: macOS Ventura, Version: 13.6.5, Size: 11916934KiB, Build: 22G621, Deferred: NO
* Title: macOS Ventura, Version: 13.6.4, Size: 11912664KiB, Build: 22G513, Deferred: NO
* Title: macOS Monterey, Version: 12.7.5, Size: 12116686KiB, Build: 21H1222, Deferred: NO
* Title: macOS Monterey, Version: 12.7.4, Size: 12117810KiB, Build: 21H1123, Deferred: NO
* Title: macOS Monterey, Version: 12.7.3, Size: 12109975KiB, Build: 21H1015, Deferred: NO
* Title: macOS Big Sur, Version: 11.7.10, Size: 12125478KiB, Build: 20G1427, Deferred: NO
* Title: macOS Catalina, Version: 10.15.7, Size: 8055650KiB, Build: 19H15, Deferred: NO
* Title: macOS Catalina, Version: 10.15.7, Size: 8055522KiB, Build: 19H2, Deferred: NO
* Title: macOS Catalina, Version: 10.15.6, Size: 8055450KiB, Build: 19G2021, Deferred: NO

Older releases

Use https://github.com/ninxsoft/Mist for older releases, including Mac OS X Lion 10.7.5.