Gareden Kerz, Grand-Pillager

Other Human creatures you control have Riot.
(This creature enters the battlefield with your choice
of a +1/+1 counter or haste.)
Whenever a Human creature you control deals
combat damage to player exile the top card of
their library, you may cast nonland and
noncreature spells exiled this way until end of
turn. You may spend mana as thought it was any
color to cast spells exiled this way.