Baldin, Century Herdmaster

As long as it's your turn, each creature assigns combat damage equal to its toughness rather than its power.
Whenever Baldin, Century Herdmaster attacks, up to one hundred target creatures each get +0/+X until end of turn, where X is the number of cards in your hand.

Jolrael, Mwonvuli Recluse

Whenever you draw your second card each turn, create a 2/2 green Cat creature token.
{4}{G}{G}: Until end of turn, creatures you control have base power and toughness X/X, where X is the number of cards in your hand.

Masumaro, First to Live

Masumaro, First to Live's power and toughness are each equal to twice the number of cards in your hand.

Sergeant John Benton

Trample, haste
Share Intelligence — Whenever Sergeant John Benton deals combat damage to a player, you and that player each draw that many cards.

Multani, Maro-Sorcerer

Shroud (This creature can't be the target of spells or abilities.)
Multani, Maro-Sorcerer's power and toughness are each equal to the total number of cards in all players' hands.

Empyrial Plate

Equipped creature gets +1/+1 for each card in your hand.
Equip {2}

Inner Calm, Outer Strength

Target creature gets +X/+X until end of turn, where X is the number of cards in your hand.

Kiyomaro, First to Stand

Kiyomaro, First to Stand's power and toughness are each equal to the number of cards in your hand.
As long as you have four or more cards in hand, Kiyomaro has vigilance.
Whenever Kiyomaro deals damage, if you have seven or more cards in hand, you gain 7 life.