You may sacrifice a creature with a mana value of 0, such as a token creature that's not a copy of another permanent, to cast a spell for its emerge cost
ANCIENT ADAMANTOISE Hard to remove, protects you and your board from damage, and drops treasures when it dies
You can tell the top-down design here, where someone asked: If I design a card to be a moat, what would it look like? It might not be the most powerful, especially when decks dont necessarily need to attack to win, but its still cool and combines well with cards that enable flying

Gallery and List of Toxic Cards Creatures With Toxic Annex Sentry Basilica Shepherd Bilious Skulldweller Blightbelly Rat Bloated Contaminator Bloodroot Apothecary Branchblight Stalker Contaminant Grafter Crawling Chorus Duelist of Deep Faith Dune Mover Flensing Raptor Glissa's Retriever Ichorspit Basilisk Indoctrination Attendant Ixhel, Scion of Atraxa Jawbone Duelist Karumonix, the Rat King Mite Overseer Monument to Perfection Myr Convert Necrogen Rotpriest Nimraiser Paladin Paladin of Predation Pestilent Syphoner Plague Nurse Porcelain Zealot Ribskiff Sheoldred's Headcleaver Skrelv, Defector Mite Slaughter Singer Stinging Hivemaster Tainted Observer Tyrranax Atrocity Tyrranax Rex Unctus's Retrofitter Venerated Rotpriest Venomous Brutalizer Venser, Corpse Puppet Vishgraz, the Doomhive Voidwing Hybrid Cards that Grant Toxic Toxic Matters Cards These cards don't necessarily have or grant toxic, but mention the mechanic by name in one way or another

The most iconic element of The Lord of the Rings is the One Ring itself: the treasureand temptationof Sauron's power
No restrictions were placed on future cards printed at lower rarities