This is a
goldmine, though I wonder no one has posted it yet (I searched twice, and didn't find anyone posting this, in case someone did, feel free to remove this post!)
This is the Pandora's box:
https://the-eye.eu/public/
This is books section
https://the-eye.eu/public/Books/
This is IT/Technical books specifically
https://the-eye.eu/public/Books/IT%20Various/
This is Microsoft Specific IT/Technical books:
https://the-eye.eu/public/Books/Microsoft/pdf/
This is for Dummies section:
https://the-eye.eu/public/Books/For%20Dummies/
NOTE: Its too good to be true, I hope its not a honeytrap