Eclipse Community

Win32 API Documentation Project:

https://randallhyde.com/AssemblyLanguage/Win32Asm/kernelref.pdf
https://randallhyde.com/AssemblyLanguage/Win32Asm/GDIRef.pdf
https://randallhyde.com/AssemblyLanguage/Win32Asm/win32apidoc.zip
https://randallhyde.com/AssemblyLanguage/Win32Asm/win32API.pdf
https://randallhyde.com/AssemblyLanguage/Win32Asm/win32.hlp.zip

Source:
https://randallhyde.com/AssemblyLanguage/Win32Asm/

Other
http://techref.massmind.org/techref/os/win/api/index.html
https://www.alsprogrammingresource.com/win32_reference.html
https://www.alsprogrammingresource.com/win32.html
https://riptutorial.com/winapi
https://riptutorial.com/ebook/winapi
https://zetcode.com/gui/winapi/
http://winprog.org/tutorial/references.html
http://www.winprog.org/tutorial/
https://learn.microsoft.com/en-us/windows/win32/

15 Best Win32 API Books:
https://bookauthority.org/books/best-win32-api-books

Windows Programming in Assembly Language:
https://randallhyde.com/AssemblyLanguage/Win32Asm/WindowsAsmPgm/pdf/PDFWinAsmPgm.html

Linux Assembly Language Programming:
https://randallhyde.com/AssemblyLanguage/LinuxAsm/index.html

Don't forget WTL https://wtl.sourceforge.io/
It uses Win32 API underneath and this is what C++ devs like me uses, atleast used to use. (I still do, Cross Platform i use WxWidget)

M$ Docs @ GitHub:
https://github.com/MicrosoftDocs/win32
https://github.com/MicrosoftDocs/sdk-api
https://github.com/MicrosoftDocs/winapps-win32-api