Mila, Crafty Companion // Lukka, Wayward Bonder

Whenever this creature attacks, another target attacking creature you control gains indestructible until end of turn.

Whenever a creature or planeswalker you control becomes the target of a spell or ability an opponent controls, you may draw a card.

All Slivers have "Whenever this permanent becomes the target of a spell an opponent controls, you may draw a card."

Lifelink

Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.

Whenever an opponent casts their second spell each turn, draw a card.

Lifelink

Enchantment spells you cast have affinity for Auras. (They cost less to cast for each Aura you control.)

Whenever you cast an Aura spell that targets a modified permanent you control, draw a card. (Equipment, Auras you control, and counters are modifications.)

Flash

Valiant — Whenever this creature becomes the target of a spell or ability you control for the first time each turn, tap target creature an opponent controls.

At the beginning of your end step, for each player, put a +1/+1 counter on up to one target creature that player controls.

Each creature with one or more counters on it can't attack you or planeswalkers you control unless its controller pays , where X is the number of counters on that creature.