A 4-mana 4/4 creature with first strike and trample is a good beater, and it tutors up not one, but two other pieces
Some of my favorites unique to the deck are Chaos Dragon, Territorial Hellkite, Warmonger Hellkite, and Vengeful Ancestor, which force attacks to trigger Firkraag and continue to lay the smackdown themselves
Stinkweed Imp Stinkweed Imp is a powerful dredge card often seen in older formats
VII Saurian Symbiote Savage Thallid Scatter the Seeds Seed Spark Selesnya Evangel Selesnya Guildmage Shroofus Sproutsire Slimefoot and Squee Slimefoot, the Stowaway Spontaneous Generation Spore Burst Spore Swarm Sporecrown Thallid Sporemound Sporesower Thallid Sporeweb Weaver Sporogenesis Sporoloth Ancient Sprout Sprout Swarm Sprouting Thrinax
Notably if you can get this creature onto the battlefield without casting it, for example reanimating it from your graveyard, you wont have to sacrifice a creature
If you kill the Goblin to slow their ramp, they still get the other chapter effects