If you're starting from zero, the best choice is a booster box or ETB from a modern set sold near MSRP with strong chase cards
Proof Of Authentication : The e-tag features a unique QR code that's attached to the card's protective packaging
A significant point is that it starts as '0/0 + 1 counter' instead of 1/1, so if you attack once, even if it's blocked, you can cast Naturalize as is, so I think it's safe to call it a 'Naturalize-embedded' creature with high reliability
Is that a thing we wanted
With such a high creature count, we could get some pretty aggressive hits
However, you can always use cards with cycling like Lrien Revealed at the end of your opponents turn to fetch a card, and, more importantly, exile the card on top of your library to play it on your turn with no restriction