The deck lens
Give it a deck. It reads what the cards do, tells you how the deck stands against every Commander precon, and offers you swaps card by card.
No accounts, nothing saved on our side, nothing to sign up for.
Your saved decks are full. Forget one on the right and this will go through: reading a deck saves it, and the shelf will not drop an old deck to make room for a new one.
or
Haven't got a list to hand? All 166 Commander precons, ranked by how original they are, how salty, how expensive, how played and how old, each one readable from either end.