My personal favorite battle, Invasion of Ikoria, offers a flexible ability on the front that scales at different points of the game, and then sets up an outright win on the back with a giant creature that features a unique ability of its own to push through massive damage against your opponent
Eon Frolicker This card is so mean and so cute at the same time
This means you could have it come in as a fetch land, or a land that can turn into a creature, or countless other amazing land cards that Magic: The Gathering has released over its many years
This makes all of your Rats much better in combat, forcing your opponents to trade their creatures if they want to block a Rat, which will then give you more Rat tokens as another creature dies.
If youre the monarch, instead you may put a creature or land card from your hand onto the battlefield
However, in most cases, a 40-card deck will provide more consistency in drawing your best cards, and I would prefer that over a diluted 60-card configuration