It can only be the commander, since your Commander deck has to be exactly 99 cards (100 with the commander), while Yorion requires your deck to have 20 more cards than the minimum to be the companion
Izzets Cauldron is currently dominating the Standard game format, which is composed of recent sets that get rotated out on a three-year cycle (although it used to be two years)
This is also known as the standard playing card size, or the regular playing card size used in the board game industry
Description Each pack contains 12 Magic cards, including 1 Mystical Archive card (Uncommon, Rare, or Mythic Rare), 1 Lesson card (Common, Uncommon, Rare, or Mythic Rare), 1 Rare or Mythic Rare, 1 foil of any rarity, 1 Wild Card of any rarity, 6 assorted Commons or Uncommons that are thematically connected (with Commons connected to other Commons, and Uncommons connected to other Uncommons), and 1 Land cardplus 1 Art Card and 1 Ad/Token or special card from Magics history (a card from The List)
Rather like the white deck, piloting this goblins list is a matter of sequencing and understanding which cards to cast first to deal the most damage
The flexibility of being able to play on either side is a bonus
