Key Objects Library and Mirror Classes Kit (KOL&MCK) for Delphi
Key Objects Library and Mirror Classes Kit (KOL&MCK) and attendant components for Delphi from Delphi2 to DelphiXE is an alternative to VCL to create small applications for Windows platform, freeware with sources. Project was started in 2000, dozens of programmers have created a lot components, helped in fixing a lot of bugs, write pieces of code in the KOL itself.
Widgets library contains c++ classes of GUI widgets for WinAPI.
NorthNotch Software Widgets Library 0.7.2 Widgets library contains c++ classes of GUI widgets that can be used in your C/C++ WinAPI applications, it contains widgets used in ShutMeDown application and there will be added more widgets in the future. Library is provided under LGPL 3.0 and BSD 2 licences
Specter - Abstract Arithmetics Library (AAL) is a library coded in native C which is able to do operations with numbers of virtually unlimited length. Specter is targeting mainly cryptography and big integer maths though.