Okay, once again a more casual list, but I think there’s a seed of something here.

creatures (28) 4 Zurgo Bellstriker 3 Lightning Berserker 4 Mardu Scout 2 Tymaret, the Murder King 3 Vaultbreaker 1 Goblin Heelcutter 4 Goblin Rabblemaster 3 Mardu Strike Leader 4 Purphoros, God of the Forge spells (9) 1 Hammer of Purphoros 4 Hordeling Outburst 4 Dragon Fodder lands (23) 4 Temple of Malice 4 Bloodfell Caves 4 Bloodstained Mire 2 Mana Confluence 2 Swamp 7 Mountain

There’s plenty of other options. If you want to go more black, both Mardu Shadowspear and Bloodsoaked Champion would be great. However, its better to just splash one of the colors. This could work even better as a purely red list:

creatures (28) 4 Zurgo Bellstriker 4 Lightning Berserker 4 Mardu Scout 4 Vaultbreaker 4 Goblin Heelcutter 4 Goblin Rabblemaster 4 Purphoros, God of the Forge spells (9) 1 Hammer of Purphoros 4 Dragon Fodder 4 Hordeling Outburst lands (23) 23 Mountain

Or with white:

creatures (18) 4 Goblin Rabblemaster 4 Brimaz, King of Oreskos 4 Purphoros, God of the Forge 4 Vaultbreaker 2 Monastery Mentor spells (18) 4 Raise the Alarm 4 Hordeling Outburst 4 Dragon Fodder 4 Secure the Wastes 2 Hammer of Purphoros lands (24) 4 Temple of Triumph 4 Battlefield Forge 2 Mana Confluence 4 Wind-Scarred Crag 6 Mountain 4 Plains

I think the Vaultbreaker in each of these lists is a key card, because it can help dig for the Purphoros, without which the decks are just trying to go wide.