Fantasy Grounds is a virtual tabletop application, which contains a set of tools to help tabletop RPG players play in person or remotely
VTT
Here you will find links to virtual tabletops. If you know other links, don't hesitate to suggest them on the home page!
The websites
Foundry VTT is a standalone application built for experiencing multiplayer tabletop RPGs using a self-hosted application where players connect directly through the browser.
Roll20 is a website offering tools for playing role-playing games on a remote table, in particular a virtual game table.