Three random Explorer examples:

https://devblogs.microsoft.com/oldnewthing/20230911-00/?p=10...

https://devblogs.microsoft.com/oldnewthing/20230324-00/?p=10...

https://devblogs.microsoft.com/oldnewthing/20220613-00/?p=10...

For code injection into applications that don't load third-party DLLs as plugins, see, e.g., Microsoft's (unsupported) toolkit for runtime API interception:

https://github.com/microsoft/Detours