Source code of the Object Pascal Handbook is now shared on GitHub
Source code of most of my old Delphi books is also on GitHub
TurboPack is a collection of classic Delphi libraries maintained by the community (with large contributions by Roman).
For information, see http://turbopack.net (currently an alias for https://github.com/TurboPack)
A simple runtime Obejct Inspector for Delphi applications.