Proxmark3 is the swiss-army tool of RFID, allowing for interactions with the vast majority of RFID tags on a global scale. Originally built by Jonathan Westhues, the device is now the goto tool for RFID Analysis for the enthusiast. Iceman repository is considered to be the pinnacle of features and functionality, enabling a huge range of extremely useful and convenient commands and LUA scripts to automate chip identification, penetration testing, and programming.
When they say to read the manual, read the manual.
The nfcpy module implements NFC Forum specifications for wireless short-range data exchange with NFC devices and tags. It is written in Python and aims to provide an easy-to-use yet powerful framework for applications integrating NFC. The source code is licensed under the EUPL and hosted on GitHub. Release versions are published on PyPI for pip install -U nfcpy. Documentation for latest development and active release versions can be found on Read the Docs. The GitHub issues tracker is the place for bug reports or related questions. Other questions may have been or get answered on the project's Launchpad answers page or stackoverflow.
A tutorial on making printable envelope templates in OpenOffice.org.