You can't overlook the hand-smoother mechanic in Arena's best-of-one games
For example, Archenemy cards, such as those in the MTG - Duskmourn Commander Deck, are 3.5 to 5 inches
UR Ultra Rare Priestess with Eyes of Blue X LIGHT Level 1 [ SpellcasterTunerEffect ] ATK 0 DEF 0 When a card or effect is activated that targets this card (Quick Effect): You can send 1 Effect Monster you control to the GY, and if you do, add up to 2 "Blue-Eyes" monsters with different names from your Deck to your hand
Jeskas Will becomes truly degenerate when you start to recur it, copy it, or find other ways to play multiple copies of it in a turn
Kolaghan Warmonger from March of the Machine: The Aftermath has a repeatable effect to dig through the top of your library and pull out dragon cards to your hand
"Madolche Magileine" and "Madolche Ticket" are easily capable of searching for other monsters from the Deck, and "Madolche Marmalmaide" can recycle Spells and Traps, which are likely the only cards that will stay in the Graveyard