Soulflayer

Creature cards that have abilities that grant the listed keyword abilities to themselves won’t count. For example, exiling a Battle Brawler (a creature with “As long as you control a red or white permanent, Battle Brawler gets +1/+0 and has first strike”) with Soulflayer’s delve ability won’t cause Soulflayer to have first strike, even if you control a red or white permanent.

You can’t exile more cards from your graveyard than you’d need to pay Soulflayer’s generic mana requirement. In most situations, this means you can’t exile more than four cards, even if you want to exile more to give it extra abilities.