Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Hans Eriksson

Whenever Hans Eriksson attacks, reveal the top card of your library. If it's a creature card, put it onto the battlefield tapped and attacking defending player or a planeswalker they control. Otherwise, put that card into your hand. When you put a creature card onto the battlefield this way, it fights Hans Eriksson.