As usual, whenever a commander gives any buff to a particular creature type, everyone is building it as tribal, which seems to be the case here, despite the fact that Kratos gives a very minimal boost to gods, since you only get one experience per attack regardless how many gods you swing with, and many of the gods tend not to die very easily, particularly the Theros enchantment ones, which rarely leave the field at all, but if they do it's generally to exile, plus they're not even gods until they're animated.
That said, there's still some potential shenanigans to be had by using gods to get more experience - some of the cheaper changelings, like Unsettled Mariner are a decent option, though really proliferate is probably more cost effective. Another option is cheap clones like Phantasmal Image cloning Kratos, which immediately generates 2 experience and is a decent card for other purposes. The one god-god I can see some value from is Ojer Axonil, Deepest Might // Temple of Power---it can die repeatedly, can be brought back easily with Areus, and paired with Kratos can send Atreus's damage stratospheric. Ojer Pakpatiq, Deepest Epoch // Temple of Cyclical Time is a lot less exciting, but still solid.
The duo obviously have a pretty clean curve of 3 into 4, so ramp isn't terribly useful outside of 0-1 mana options which are few on the ground and tend to be game changers. So with draw and wincon largely handled and ramp of limited usefulness, and at most a couple spots dedicated to advancing experience counters beyond what Kratos provides on his own, we've got lots of spots available for disruption. Hooray! We're making another control deck. Who could have imagined this from me?
One other aspect worth mentioning - haste isn't SO key to where I think it's worth going super deep on it, but at the very least I think some lands like Arena of Glory and Hall of the Bandit Lord are worth including, since they let Kratos generate experience counters immediately after getting played if Atreus isn't available to attack (say if it's post board wipe) and let Atreus use his ability to generate card advantage more reliably. We could also chuck in stuff like Anger since Atreus is a built-in discard outlet. I don't think there's any madness cards really worth playing for value, but maybe I'm missing stuff.
Besides haste I don't think we'd be looking for too much from our lands besides fixing, since Atreus should hopefully be generating enough CA that we'll be able to keep ourselves busy. I do think we want a decent land count so that we're not stumbling on our way to 4, though, that'd be really bad. So at least 40, probably 45. I do probably want to run channel lands and such, though, so we're not bricking as hard on them late-game.
Oh yeah, Sage of Hours is probably worth running here. Not really my cup of tea but at least there's a lot of setup cost.
So like broad brushstrokes here:
10 synergy (gods/proliferate/sage of hours)
20 counters
20 removal
5 wipes
45 land
To drill down on proliferate specifically, the best picks are probably:
Thrummingbird
Flux Channeler
Ripples of Potential (maaaaybe?)
Experimental Augury
Staff of Compleation
Grateful Apparition
Contentious Plan
Norn's Choirmaster (double attack trigger is pretty nice)
Serum Snare
Patrolling Peacemaker
Guildpact Informant
Dreamtide Whale
Roaming Throne
Man, trying to build a deck for a commander I won't even have for another...month?...is rough. How many sets are going to come out in the meantime? A dozen?
Atheist Kratos
