Deck diff
Paste the old list and the new one. Cards are matched by name, so a new printing is no change.
Import this into Reliquary
A free account keeps every card in the one place it is, and your assistant can read it.
With Google or GitHub. No card.
More free tools
Decklist converterMoxfield, Archidekt, Arena, MTGO and TappedOut text
Collection CSV converterAny collection app’s export to Moxfield or Deckbox
Legality checkerA decklist against every format, and its colour identity
Decklist priceWhat a list costs, card by card
Collection valueWhat a collection export is worth
Registration sheetA decklist as a PDF to hand in at an event
Draw oddsThe chance to draw a card by each turn