Council of Europe Treaty Collection
The text of all Council of Europe treaties, their explanatory reports, the status of signatures and ratifications, the declarations and reservations made by States, as well as the notifications issued by the Treaty Office since 2005, are available on this website.
Avalon Project from Yale Law School
This project provides digital copies of historical diplomacy documents including treaties.
WorldLII
This site collects laws, treaties, cases, journals, and other materials from around the world. It covers both foreign and international law.