Play

Non official softwares

Cockatrice

https://cockatrice.github.io/
Virtual tabletop cardgaming software
Supports Magic and other games

Free software
Systems : Windows, Linux, MacOS
Note : Preconfigured for Magic The Gathering with english cards included but with no rules implemented

Ocgtn

http://www.octgn.net/

Virtual tabletop cardgaming software
Support many Magic and many other games (see http://octgngames.com/ )

Free software
System : Windows
other systems : https://github.com/octgn/OCTGN/wiki/OCTGN-on-non-Windows-systems
Note : All games module for octgn can be installed with menu « game manager »

Xmage.de

http://xmage.de/

XMage allows you to play Magic against one or more online players or computer opponents. It includes full rules enforcement for over 10,000 unique cards (nearly 20,000 counting all cards from different editions).

Free software
System : Windows / Linux / Java platform

Official Softwares

Magic The Gathering Arena
https://magic.wizards.com/fr/content/magic-gathering-arena
Magic The Gathering Online 
https://magic.wizards.com/fr/products/magic-online
Magic The Gathering Online for Linux & MacOS (with docker)
https://github.com/pauleve/docker-mtgo
Magic Duels
https://magic.wizards.com/fr/products/magic-duels

Manage

Cards database

https://scryfall.com/

https://www.frogtown.me

https://gatherer.wizards.com/

Deckbuilders

http://www.lotusnoir.info/magic/decks/
http://tappedout.net/mtg-deck-builder/
http://www.magic-ville.com/fr/decks/
http://splizard.com/magic/decker/ – Multi cardgame deckbuilder (magic, pokemon, yugihoh, …) for Tabletop simulator