Here is the completion of red and a lot of green.
Goblin Goon (3.607) In a Goblin deck you will have more creatures and its a 4-drop 6/6.
Goblin Ringleader (4.276) Get Goblins out of the top of your deck.
Goblin Settler (3.689) Land destruction. Acidic Slime's red cousin.
Lightning Dragon (4.088) Broken Urza card. A 4-drop 4/4 flyer that can be pumped.
Pillaging Horde (3.792) Tibalt deck. Undercosted.
Clickslither (3.933) Goblin devotion deck.
Burning of Xinye (3.717) Like Wildfire and Armageddon.
Crater Hellion (4.317) Urza broken card. If you have no creatures this card is a board wipe.
Fireblast (4.466) Two lands for 4 damage free-casted.
Scourge of the Throne (3.969) Conspiracy limited bomb.
Rorix Bladewing (4.169) Nice dragon. Good in limited AND constructed.
Worldgorger Dragon (4.306) Another nice dragon, this one with trample.
Flicker combo madness is worth experimenting with.
Berserk (4.921) ABU card. Big hit from your creature and then creature dies. Play it with Regrowth.
Fyndhorn Elves (4.551) Functional Llanowar elves.
Hermit Druid (4.436)
Worth a build-around experiment.
Gatherer:
"... you run all non basic lands, you mill your whole deck putting 2-3 narcomeobas in play, flashback dread return targeting suture ghoul and removing lord of extinction getting a 40-50ish power trampling ghoul, dragon breath comes out of the graveyard to give it haste. It is a one card turn 2-3 kill, and that is why it is banned in legacy."
Nature's Lore (4.095) Forest can get you a legacy dual or a Shockland.
Kaervek's Torch (4.506) X damage spell. A better Blaze.
Starstorm (4.078) Board wipe.
Armor of Thorns (3.149) Limited enchanter.
Brindle Shoat (3.438) Light Thragtusk or a green Doomed Traveler.
Dreampod Druid (3.618) Once a turn token dropper. Combine with Modern Masters fungus.
Provoke (3.520) Instigator.
Survival of the Fittest (4.589) Amazing card: uncounterable tutor in green.