Cockatrice is an open-source multiplatform software for playing card games, such as Magic: The Gathering, over a network. It is fully client-server based to prevent any kind of cheating, though it supports single-player games without a network interface as well. Both client and server are written in Qt, supporting both Qt4 and Qt5.
Get Started
Download a installation file or compile your own
Install 'Cockatrice' application
Run 'Oracle' tool to create a card database (or import one)
Open 'Cockatrice' and start building a deck (or import one)