macOS in App Store

OSX 10.9 Mavericks
https://apps.apple.com/app/id675248567

OS X 10.10 Yosemite 
https://apps.apple.com/app/id915041082

OS X 10.11 El Capitan 
https://apps.apple.com/app/id1147835434

macOS 10.12 Sierra
https://apps.apple.com/app/id1127487414

macOS 10.13 High Sierra 
https://apps.apple.com/app/id1246284741

macOS 10.14 Mojave
https://apps.apple.com/app/id1398502828

macOS 10.15 Catalina
https://apps.apple.com/app/id1466841314

macOS 11 Big Sur
https://apps.apple.com/app/id1526878132

macOS 12 Monterey
https://apps.apple.com/app/id1576738294

macOS Ventura 13
https://apps.apple.com/app/id1638787999

macOS Sonoma 14
https://apps.apple.com/app/id6450717509

Apple - How to get old versions of macOS https://support.apple.com/HT211683
Apple - How to create a bootable installer for macOS https://support.apple.com/HT201372

Mac OS X 10.7 Lion Installer
https://support.apple.com/kb/DL2077
https://updates.cdn-apple.com/2021/macos/041-7683-20210614-E610947E-C7CE-46EB-8860-D26D71F0D3EA/InstallMacOSX.dmg

Mac OS X 10.8 Mountain Lion Installer
https://support.apple.com/kb/DL2076
https://updates.cdn-apple.com/2021/macos/031-0627-20210614-90D11F33-1A65-42DD-BBEA-E1D9F43A6B3F/InstallMacOSX.dmg

OS X 10.10 Yosemite
http://updates-http.cdn-apple.com/2019/cert/061-41343-20191023-02465f92-3ab5-4c92-bfe2-b725447a070d/InstallMacOSX.dmg

OS X 10.11 El Capitan
http://updates-http.cdn-apple.com/2019/cert/061-41424-20191024-218af9ec-cf50-4516-9011-228c78eda3d2/InstallMacOSX.dmg

macOS 10.12 Sierra
http://updates-http.cdn-apple.com/2019/cert/061-39476-20191023-48f365f4-0015-4c41-9f44-39d3d2aca067/InstallOS.dmg