https://magic.wizards.com/en/mtgarena (The place to download the game)
https://aetherhub.com/Banlist (List of banned and suspended cards on Magic Arena)
https://twitter.com/MTG_Arena (Magic Arena's official twitter)
https://magicthegatheringarena.statuspage.io/ (Magic Arena's status page)
https://scryfall.com/ (The best Magic: The Gathering card search engine)
https://www.mtggoldfish.com/metagame/#paper (A good place to check the meta out)
https://mtgarena.pro/ (Another good place to check the meta out)
https://whatsinstandard.com/ (A guide of what's in Standard, what will stay when rotation happens and when rotation happens)
https://cardgamebase.com/mtg-arena-codes/ (A list of all the codes you can redeem on Arena)
https://mythicspoiler.com/newspoilers.html (A place with all the spoilers for the upcoming cards coming to Arena)
https://www.mtgpics.com/ (The best place to look for card art at full resolution)