a deck can have any number of cards named mtg RELENTLESS RATS X4 Masters 25 Magic MINT CARD The ANY NUMBER of Cards

It starts outside the game and doesn't count as one of your 100 cards

Or as many as you can keep around as you attack turn after turn

Pointing out that another player has a tremendous battlefield state (or making a sacrificial attack into it to demonstrate), that a player has drawn a ton of cards, or that youre underdeveloped compared to everyone else only matters if your opponents cannot assess threats

Court of Cunning Mill got a ton of new toys with Zendikar Rising , and Commander Legends gives us at least a few more

Typically, the Commander RC bans one card, maybe at times unbanning another at the same time, which keeps expectations in check for fans and makes for steady updates to the rules

If youre already empty-handed, you still get the 4/3