We may all be quarantined at home, but I'm not going to let that get between me and my weekly cube draft night. I bought an entire copy of my cube on Magic Online so I could keep drafting and iterating on it even while we can't gather in person. Is it more of a pain than drafting a first-party cube? Without a doubt. But you can do it with your friends, at any time, using your cube list.
This document will walk drafters through the process of drafting their decks and acquiring them on Magic Online. It requires a host who owns all the cube cards in the first place and who knows how to trade them to the drafters--I've also written a guide to hosting a draft if that's what you're looking for!
This was written in May 2020, and some details of how things work may change in the future. Feel free to post updates in the comments, or even just fork this and modify it as necessary.
The best place to draft a custom cube with a table full of other human drafters is dr4ft.info.
When it's time to draft, the host will send you a link to the draft page. Keep this page open: it's where the entire draft will take place. First, update your drafter name to be your Magic Online screen name:
Having your screen name here will make it easy for the host to trade your cards to you and for other players to challenge you for matches. There are also settings to the side that you can fiddle with to your preference.
Once the draft begins, you'll see a pack of cube cards. Clicking a card once will reserve it so that it'll be picked if the pick timer runs out. Clicking it a second time will add it to your deck.
You can see the cards you've drafted below the draft. If you click a card in your main deck, it'll move it to your sideboard, and vice versa. Cards in your sideboard on dr4ft.info will also show up in your sideboard on MTGO!
Note: All dr4ft.info drafts have timed picks, but you can only see the timer if your browser window is scrolled down close to the pack of cards you're picking from.
Once everyone's done drafting, you'll be able to download the deck you drafted. Update the deck name to your Magic Online username, make sure the format is set to txt, and click "Download As".
This will download a text file that Magic Online can use to create a decklist for you. If you're using Chrome, this file will end up in your "Downloads" folder.
Next you'll need to send the text file you just made to the host so they can trade you your cards. You can use any common means of sending a file to another person, but since I use Discord to communicate with drafters I find it easiest to just drag the file into a Discord chat.
The next step is to open Magic Online. By this point you're probably chomping at the bit to start battling, but first you'll need to finalize your decklist and get the cards you need from the host.
First you'll need to tell Magic Online which cards are in your deck. You probably don't have these cards in your collection yet, but don't worry, you'll get them later. You can still build your deck without them for the time being.
Warning: The names dr4ft.info uses for split cards like Connive/Concoct and adventure cards like Murderous Rider are different from the names MTGO uses), and this will totally break your import process. If you drafted one of those cards, even if it's in your sideboard, you'll need to open up your decklist in Notepad and edit the card name. Split cards need to have exactly one slash and no spaces between the words, like 1 Connive/Concoct; adventure cards should just have their creature name, like 1 Murderous Rider.
Once you're ready to import, go to the Collection tab and click the deck box in the lower left-hand corner. Don't click the binder!
Click the big Import button.
Find the decklist file you exported in step 4, and click "Open".
Finally, click "OK".
You should end up seeing your picks in a deck like this one:
Now you can start building your deck! You can drag cards you don't want in your main deck into the sideboard section. Warning: unlike in a Magic Online draft, double-clicking a card will remove it from your deck entirely rather than moving it to your sideboard! If you want it back, you'll need to either search for it in the top pane with "Quantity" set to zero or just re-import your deck.
To add basic lands, right-click the background and select "Add Land to Deck". I strongly recommend adding a few extra basic lands to your sideboard if you think you may want to side them in, as basics can't be added to your pool during sideboarding otherwise.
If you're doing a team draft, you may want to get on voice chat or into a discord room and share your decks. I recommend the snipping tool for that!
Note: this may happen in parallel with step 6.
The host owns all the cube cards, so they'll need to open a trade window with you to give you those cards. When they do, click "Accept". Magic Online may ask you to select a trade binder; if so, it doesn't matter which one you choose.
Once the trade window is open, the host should have your exact decklist available for you. If you don't see 45 cards, click "Reset All Filters". Click on one of the cards, press Ctrl+A, drag everything into the "You Will Receive" box.
Click "Submit".
The trade will move to a different view once the host clicks "Submit" on their end. Click "Confirm Trade".
Once the host confirms, you'll have your cards, and Magic Online will let you submit your deck for challenges!
If you go back to your deck, it'll probably still say it's missing a few cards. That's because the versions of cards in your deck are different than the versions you just traded for. This won't actually stop you from using the deck, but if you want to fix it, right-click on your deck's background and select "Update with version(s) in collection".
It's finally time to duel! I recommend splitting into random teams after drafting, so that each drafter only plays against people on the other team. That way, you can find a match by simply asking if anyone on the other team is free.
Once you know who you're paired against, choose amongst yourself one person to be the challenger. That player will follow step 8.a, while the other player will follow 8.b.
First, add the player you're matched with as a buddy if you haven't already. To do so, click the settings gear in the upper right-hand corner, click "Buddies, Clan, and Chat", type in their username under "Buddies List", and click Add Name. If you don't know their username, you can find it in the dr4ft.info Players list (or just ask them).
Next right-click their username and select "Challenge Player. Note that you have to click the text of their username, not the highlighted bar behind it, because Magic Online is 50% spite by volume.
Make sure your draft deck is selected as the deck for the challenge and set the format to "Freeform".
It's nice to set the draft to "Watchers Allowed" so that your fellow drafters can come hang out while they're waiting for an opponent. If you do this, consider voice chatting your opponent in an open channel as well.
Once you've paintIf it looks like your opponent decined your challenge right away, make sure they've added you as a buddy and try again.
By default on Magic Online, you can receive challenges from anyone. However, if you've set yourself to only receive challenges from buddies, you'll have to click the settings gear in the upper right-hand corner, click "Buddies, Clan, and Chat", type in their username under "Buddies List", and click Add Name. If you don't know their username, you can find it in the dr4ft.info Players list (or just ask them).
Once that's done, just sit back and await the challenge. Once you receive it, select your deck and click "Accept".
Cards on Magic online do have real-world value, so the host will probably be a bit peeved if you don't return them after the draft. Tell the host when you're ready to finish up and in a few minutes they'll initiate a trade with you.
When you get the trade invite, make sure you have the "Full Trade List" binder selected. The host will make sure to only take the exact cards they traded you. Then click "Accept".
The host will select the exact 45 cards they need returned. Once they've done that, click "Submit" and "Confirm Trade" like you did before and you're done!
Unfortunately, I don't know of one.