Rather than leave one The Biblioplex in the sideboard, simply play both and cut a spell for the second one
Poison is just not what most people like to see in their casual Commander games, and it made the players who like Phyrexian lore and aesthetics feel unfairly singled out by association
"Pooh Pirate Ship," an Item card, returns a Pirate card from the discard pile to the player's hand - great for second chances
Having access to hard-lockout condition is a great way to give yourself a chance in any matchup, plus you can close out the game quickly by turning it into a 6/6 with Karns less-talked-about plus ability
The calamity of Sin is endless and the cycle keeps repeating, because when Sin is defeated by the summoner, the summoners guardian becomes the new Sin
FINAL FANTASY COMMANDER: BLACK I mentioned playable graveyard hate previously, and Espers to Magicite is another solid example