A rainbow list built around Roughrider and Allfather's horn. Still a work in progress but this is a solid version of the list. It lacks removal so tweak as necessary. Although it has horn as a finisher it's quite a fair list -- frankly a little too fair for the current meta as it's neither hyper aggro and still needs to stick minions against control. Kind of a decent tier 2-ish list.
I think the deck is very fun. It plays a suite of midrange minions with solid stats and divination effects to draw a lot from rainbow while putting out threats. It looks to get in some early chip damage and then beatdown the opponent with big overrun / agile minions on enchants and/or an Allfather's Horn combo.
The list skews slightly more towards blue than orange, which might appear a little odd considering rough rider's effect but I haven't found it too restrictive. It's something you have to consider when selecting your burns early in the game, but for the finisher even 2O with rough rider will usually put you at overkill with horn as it's 12 damage burst + 2 for infuse + double whatever enchant you are standing. When looking for horn lethals, always remember to proc rough rider before refreshing your gems, and that you can play enchants onto the field after horn as well as fragile effects or extra minion damage to help ride over their face.
Beserkrgangr is a fun card that's not entirely necessary but very cool. Playing him on plateau is nice if you have other enchants adjacent.. Also good to note that Armageddon Angel gets the frenzy before wiping the board, so you can revisit the old days of angel being a proper game ender.
Insurrectionist is surprisingly a potential cut. It's nice for rough rider redundancy, to smooth the curve and as a late game play when going wide with 2 bodies has more value than 1, but a lot of the time your other minions are better as immediate threats. It's good at what it does but on curve it feels pretty bad.
One obvious missing card that I think stands out is Freki Sidecar. This seemed like it would be necessary, and early variants of the deck were born out of me salivating over Beserkr --> Freki --> Roughrider combos. But in practice it just felt clunky. I don't want it early and it doesn't help with your horn lethals later. It does give you extra reach - especially if you have giant's stairway set up - but in most games I've needed a little bit more than the 7 or so you could reasonably expect to actually end. I may try to find space for 1 again at some point.
One final note the deck has no heal and draws quite a bit from rainbow, so you need to be careful with incidental damage from Ifreet. The deck lacks healing in general, and Mend might actually be a good alternative to Infuse. Infuse is mostly there for ending the game. Mend is actually better versus aggro. Infuse better against control. Switch it up if needed.