I've been brewing a version of Krenko myself (albeit, a slower, more casual brew) and thought I'd raise a discussion point around a couple of cards and get peoples opinions on them.
The first is
Anger.
A commonly used haste enabler, but I can't see it covered in the single card discussion (apologies if it is and I missed it). Particularly good if a lot of your draw is based around drawing and discarding (as red often is) as it's essentially a "free" (minus the cost of, you know, including it in your deck in the first place) haste enabler when you discard it.
The obvious downsides are that you need to be able to reliably put it in the bin and graveyard hate will remove your haste enabler. Are these downsides your reasons for not including it? Given how frequently it is used (29k decks on EDHRec), it seems potentially worth a line in the card discussion.
I've personally found it to be very useful, but my deck utilises more draw/discard than yours and graveyard hate in my meta isn't a massive issue.
The other card is
Den of the Bugbear.
Not sure if you've worked much on this primer since this card came out, but it's another outlet for infinite mana that just wins you the game. Given the speed of this deck compared to a more casual Krenko deck, the chance of it entering tapped might not be worth the cost of inclusion, but I'd be interested to hear your thoughts on it.
Just to confirm, the rulings on
Den of the Bugbear taken from Gatherer as I wasn't sure if it would work this way when I first read it:
"If
Den of the Bugbear's last ability is activated multiple times in one turn, it will have multiple instances of the triggered ability that it grants. For example, if you activate it twice and attack, you will create two 1/1 red Goblin creature tokens that are tapped and attacking."