If you have some on-color fetch lands lying around, of course include those
The creatures must share at least one creature type, such as Ally or Lemur
This means that, should you try to get cards during your opponents turns, you may be disappointed
Free Spells Cards that go into your graveyard like Mishra's Bauble and Once Upon a Time count as a different type of card for effects like delirium and replace themselves
Honorable Mention #2: Tradewind Rider If this list were Top Ten Spirits for Standard, this would be a clear #1 since it dominated the era with multiple egregious decks like Trade-Geddon where you cast Armageddon and then bounced every new land with this, which I built, or Trade-Awake with Awakening to untap each turn all stuff for more bounces
All you lose out on here is Deathtouch, so Black Cat is set to usurp Gontis throne