One example: a 1996 Pokmon Japanese Base Set Venusaur with an artist autograph just set a record for any Venusaur card ever at $55,000

A Good Thing (playtest) A Killer Among Us A Little Chat A Most Helpful Weaver A Trail of Teacups Aang's Iceberg Abandoned Outpost Abhorrent Overlord Abjure Aboroth Abstruse Interference Abzan Banner Abzan Monument Accursed Centaur Ace, Fearless Rebel Acidic Dagger Acidic Sliver Acolyte of Aclazotz Acridian Ademi of the Silkchutes Adric, Mathematical Genius Adverse Conditions Aeolipile Aerial Toastmaster Aerie Ouphes Aether Spellbomb Aetherjacket Afiya Grove Aftermath Analyst Agatha's Champion Age of Ultron Agency Coroner Agent 13, Sharon Carter Agent of Shauku Agent's Toolkit Aggressive Mining Ahn-Crop Invader Ahriman Ainok Strike Leader Air Nomad Legacy Airdrop Condor Airship Engine Room Ajani Fells the Godsire Ajani's Aid Ajani's Last Stand Akki Avalanchers Akki Scrapchomper Akul the Unrepentant Akuta, Born of Ash Albino Troll Alchemist's Apprentice Alchemist's Talent Alchemist's Vial All-Fates Scroll Ally Encampment Alpine Guide Alquist Proft, Master Sleuth Alseid of Life's Bounty Altar of Bone Altar of Dementia Altar of the Wretched Altar's Reap Amateur Auteur Ambush Commander Amphin Mutineer Amulet of Quoz An Offer You Can't Refuse An Unearthly Child Ancestors' Aid Ancestral Carvings Ancestral Knowledge Anchor to Reality

Even without that, Role tokens offer a ton of powerful abilities you can give your creatures
Even if it dies, it becomes a land to make it much harder to permanently get rid of
All must be one, and while converting the populace into Phyrexians is one way to go about it, simply popping out more nightmares can be a quick and nasty way to build up an army