Alternate deck title: Big Codex Energy

This is a somewhat long and convoluted infinite combo that wins you the game on the spot with Darksteel Reactor. It requires very little setup/luck to get the pieces right, but the downside is that the deck is absolute crap at everything but the one combo it revolves around.

I've tested this entire combo sequence in Arena, and can verify that mechanically it definitely works.

Setup required

1: Deal damage to your opponent during a turn where you think you can still get the rest of this off as well. Sunscorched Desert is really useful for this, especially since you naturally want to delay playing it since it's a colorless land.

2: Use Codie, Vociferous Codex to cast Repeated Reverberation (You should tap this manually to make sure you both use Codie and have red mana left).

3: Have any additional card in your hand.

4: Have the right cards in your deck (with minor flexibility). This is easy enough that I could have just not said it, but I feel I should be this complete in listing the requirements.

(Alternatively, you can try to skip Codie, but it requires a lot more work)

Infinite mana and looting

As mentioned, you gotta deal some damage, then cast the Reverberation out of Codie. This gets you a free Neoform, which will be copied by Reverberation twice, which lets you search for 3 creatures with mana value 4. We get two Famished Foragers and one Emiel the Blessed. This gets you 6 more mana, which you can use to retrieve and play Zirda, the Dawnwalker from the sideboard (companionboard?).

This means you have infinite mana, because Zirda makes Emiel cost 1 mana to flicker the Foragers, which grant 3 mana on ETB. You also have infinite looting effects (also from the Foragers), to search the entire deck for Karn, the Great Creator.

Closing it out

Once you have infinite mana, and Karn, you use Karn to grab Guardians of Koilos, to return Karn to your hand. Emiel can flicker the Guardians. Putting it all together, now you have all the artifacts in the sideboard at your disposal.

In order to win, you get Mace of the Valiant 20 charge counters, animate it (with Karn), flicker it to put the counters onto The Ozolith, animate Darksteel Reactor, and then enter a combat step in order to move the counters onto the reactor, winning the game.

Notes

The mana base is made to accomodate everything except for Emiel and Neoform, which means just blue and red; however, a few of the particular card choices make it possible that you can play them anyways, if you actually need to.

Repeated Reverberation is really important, and searching for it is expensive (not to mention there's only one copy of one card to search for it), so it's most definitely worth at least one mulligan to get it

Response//Resurgence is intended to be used for both/either of its halves. Response for general staying alive and whatnot, Resurgence in case you attack in order to deal your damage before the combo, so that you can get another combat step for The Ozolith. You don't have to worry about mana fixing for Resurgence because you're only going to play it in order to get the combo off, at which point you're guaranteed to have a Locket to fix mana.

Invert//Invent is intended mostly to be used for Invent, because Reverberation is just that important. You might also use it for Invert, just cuz generally Invert can be useful (in the loosest sense of "can").

Some of the more flexible options in the sideboard are chosen in particular just so it plays better in Arena (particularly the locket and mace).

Renowned Weaponsmith helps power Codie. Moonsilver Key can search for Codie.

Epitaph Golem can recycle cards (since you have infinite looting). This is included for Resurgence, since you may want to cast and/or cycle over all of them to get Karn.