MTGNexus

This deck had only one objective: make people pick the card to read and trying to figure why I run it, while I steal his deck. No combos, only good nonsense and ways to confuse people with a weird and fun deck. Sometimes I pay in tax for Grenzo, sometimes I trample a 6-man pod with dozen of unblockable creatures, so it's a win-win for me.

The main problem, as every monored aggro deck in the history of Magic, is that it runs out of gas very fast, and few ways to recover after a mass removal and close the game. I tried to put some ways to protect my board and grind for longer games, but seems that isn't good enough. All cards must have a foil version, because I made a mistake some years ago and now I must fulfill this madness.

I've played a Grenzo, Havoc Raiser deck in the past and I know what you mean. You can't ever have enough creatures on the board because the Goad element actually becomes a real source of where your triggers are used AND of course you want to be exiling cards as well so that you can get card advantage.
Therefore it's waaaaaay to tempting to just cast out all your creatures as quickly as you can. But alas one board wipe later and you are back to square one.

Underworld Breach is the first step in recovering from a board wipe.

Playing some mana sources that can withstand board wipes will also help long term. Your play style can adjust slightly by making sure you cast mana sources rather than flooding the board more with creatures. Then when the Wrath comes you will have kept some creatures in hand and can deploy them all quickly due to more mana sources.
Darksteel Ingot, Skyclave Relic, Wayfarer's Bauble, Sword of the Animist, Solemn Simulacrum, Burnished Hart.
Mind Stone and Commander Sphere can be used for draw in the face of a board wipe.

Another route is to use instant or sorcery that produce token creatures and then you can get revalue with cards Past in Flames and Mizzix's Mastery. Empty the Warrens, Hordeling Outburst type cards. This also means that your instant/sorcery steal cards have further reach in the deck.

Finally Red is know for it's graveyard recursion with artifacts with Scrap Mastery. You could build an artifact creature centric deck so that you always have this card to bounce back immediately. I don't know if there are enough good artifact creatures to support this idea but good to know options.

Conspicuous Snoop can be used as literally card advantage with Goblins in the deck.
Experimental Frenzy could be used to get further value.
Feldon of the Third Path for constant recurring value.
Skullclamp will help with filling your hand up.
Break Through the Line is good enough so that you don't have to throw away so many creatures to get Grenzo triggers.

Break Through the Line seems like a wonderful inclusion.