{Legion Loyalist} or {Goblin Arsonist} for a mono red goblins list in standard
You play both and {Legion Loyalist} is good with {Krenko, Mob Boss}
Boros Goblins? Damn, that actually sounds fast. I wish we still had {Goblin Grenade}...
Both are good but I'd say loyalist is more important if you need to cut copies of one. For example, if you can only fit in 6 1-drops, I'd recommend 4 loyalists and 2 arsonists.