Bloodmark Mentor, Goblin King, Mogg Sentry, or Thunderous Wrath would all fit pretty well. Also, add two more Krenko, Mob Boss.

Hellrider could also fit well.

Guttersnipe, Goblin Fireslinger, Tuktuk the Explorer

took the deck modern so I could play it more, lol

You could try also Goblinslide and Boggart Shenanigans to add more goblins and more damage per turn

Why play Zada, Hedron Grinder?

Burn at the Stake would be good here

mrweaselman: yeah, you've got a lot of good suggestions, most of which I will eventually get around to trying. Sorry if it felt like I was ignoring your advice, I just suck at finding the time to post responses. My bad.

Bloodmark Mentor, Mogg Sentry, +2 Krenko, Mob Boss, Guttersnipe, Goblin Fireslinger, and Tuktuk the Explorer... all yes. TY.

Goblin King, Hellrider: unfortunately, i'm kinda goblin-snob about this deck, and Hellrider isn't a goblin, but he may make a good sideboard card. Goblin King i've considered, and would actually like to replace Goblin Rabblemaster with 2 of him, but I definitely wouldn't replace any of the Goblin Chieftains.

Thunderous Wrath, and while we're at it, Lightning Bolt would probably make this deck better, idk, but with Goblin Grenade and Massive Raid they seem unnecessary. Though it of course serves a good purpose in my burn deck.

GoblinTaskmaster: Goblinslide I tried right away when it first came out, and I ended up not liking it because of how very few noncreature spells the deck actually runs. It actually makes the card either a dead draw or a waste of mana. Well, for me, here, anyway. Sorry man, but Boggart Shenanigans i like, and will try out one day. As a 3-drop, i may sideboard it, but we'll see.

supermill: tbh, idk. I like to playtest things on impulse at times, and this is one of those times. And you're right, there is no reason to play him in this deck. Thanks for noticing, and I'll be updating soon, when I get a suitable replacement.

amazingdan: another one I've considered, but at a 5-drop, i just don't know. Maybe as a 1-of? Sideboard? When I swap out the Zadas, I'll also see if I can slip a Burn at the Stake or two in their as well. Good idea though, TY.

You could try Goblin Guide