This is where builds between Bushwhacker Zoo decks differ, these cards can change depending on your local meta or personal preference.
Thalia, Guardian of Thraben. Some decks run her in the sideboard but I prefer three copies in my main and will board her out into other creature decks. This is because Thalia makes it more difficult for opponents to stabilize against you. Modern is often a very creature-hostile environment and turning Fatal Push,Path to Exile and Lightning Bolt into 2 mana spells forces an answer from your opponent before they can continue with their game plan. What's the difference between a T3 Anger of the Gods or a T4 Anger of the Gods? Often the game.
Boros Charm. This card is a personal all-star. It's both reach and protection for your team and both of these modes have won me games. I recommend 3.
Hidden Herbalists and Greenwheel Liberator. Herbalists is card that I both love and hate. It can extend a BTE chain and can help you flood the board with Nacatls and Renegades however, the mana it makes means you need an additional before you can cast a Bushwhacker which can make your opening hands awkward. I run 2 right now. Greenwheel Liberator is a card I am currently experimenting with as another payoff for BTE or Hidden Herbalists. Let me know what y'all think.
Ghor-Clan Rampager. Efficient pump that provides reach and cant be countered outsideStifle effects. It interacts well with the Deathtouch on Narnam Renegade. I run 1 right now.
Glorious End. Woah man, don't even trip. Is this jank? Yes. Have I punted games with this? Yes. I'll tell you this, this card is fun as hell to play. Tiny Zoo is an aggressive deck that looks to put the game away in the first 4 turns or so. If you are on the front foot and your opponent is trying to stabilize, a well timed Glorious End will seal the game for you. A lot of my games come down to crucial final turn and nobody expects red counter magic. Shenanigans with this card include:
Casting Glorious End when your opponent goes in for a lethal alpha strike, then killing them on a crackback.
Casting Glorious End at your opponent's upkeep, denying them a Draw Step, Aether Vial trigger, land drop, or crucial blocker.
Casting Glorious End on your opponents first play of their lethal turn just to dig for that last piece of burn you need to topdeck.
Lastly, casting Glorious End just to go out on your own terms. WUBBA LUBBA DUB DUUUB!!!!