Edit: I just counted it up. For the full 75, this is what a F2P player is guaranteed to already have, assuming no cards were ever unlocked through playing:
1 of 4 Mythics (Also, could be 1 of 1, as Karn is not a necessity in this deck. He is super useful in grindier match-ups of course)
15 of 25 Rares
16 of 24 Uncommons
4 of 8 Commons

You can see more of this deck on my stream @ https://www.twitch.tv/jackischmtg

Summary:
The game plan here is to gum up the board early and get out our combo pieces (the modules) as quickly as possible. Once we’ve gotten our pieces out, we’re going to spend the rest of the game setting off a billion triggers, gaining us tons of servos, thopters, +1/+1 counters, and energy.

With the summary out of the way, let’s dive in to the individual cards:

Thriving Turtles: I know this card looks like I’m meme’ing, and honestly, opponents tend to treat it that way. But this card is a great road block in the early game (Red aggro, looking at you), and an incredible enabler for our combos in the mid-late game.

Glint-Nest Crane: Solid 2 drop that gums up the board against aggro and helps us find our combo pieces and other things. The only other thing to add here is that we may want to up the artifact density of the deck just a tad more to make the trigger find an artifact slightly more often.

Whirler Virtuoso: This card is fairly well positioned in the meta. Against Red Aggro, it’s the only cheap card in the format that gives multiple bodies which don’t die to chainwhirler (you should be using the ability at instant speed, as need for trades and chump blocks). For every other deck, it’s an efficiently costed 3 drop that can leave tokens behind when they try to use their removal. Much like the turtles, this card enables our combos with the energy gain trigger, and can even go infinite with 1 Decoction Module and 1 Gonti’s Aether heart on the field. A true all-star card in this deck!

Metallic Mimic: Mimic is here as a “silver bullet” of sorts for whir of inventions. You usually want to search for mimic when you have at least 1 of each Module out on the field. In this scenario, you always want to name servo. Doing this allows you to spend your remaining X mana (and even mana on the following turns) to gain X 2/2 servos, X +1/+1 counters, and X energy. This can be a great strategy in the late game to surprise your opponent when they tap out and just go wide.

Walking Ballista: So by now you’re probably seeing that this deck can generate a ton of +1/+1 counters. Ballista is an incredibly solid card by itself, but with all the +1/+1 counters, becomes that much better. The last game I played before this write-up, I got Ballista up to 19/19 and just pinged my opponent to death. (Yes, he didn’t just concede.. xD) Also helps the F2P players who have limited wildcards, seeing as you all have 4x of these for free!

Animation Module: Tied for most important combo piece with Fabrication Module. Against control, this card enables us to almost continually create tokens, which is arguably one of the best tactics against control since it allows you to add pressure to the battlefield without committing additional cards in your hand. Activated ability is the cheapest way without playing another card to gain energy or +1/+1 counters to trigger your other combo pieces.

Decoction Module: Least important combo piece, yet having 1 on the battlefield after Animation and Fabrication have resolved is a HUGE deal. The only reason this card is less important is due to the fact that we have 14 other cards that generate energy for us just for playing them. The activated ability is also super important in the control match-ups. Sometimes, the correct play is to be conservative with your mana and ensure you can bounce your non-token creatures to dodge removal.

Fabrication Module: Tied for most important combo piece with Animation Module. This artifact is the most reliable way for us to create +1/+1 counters, which then also allows animation module to let you go wide.

Aethersphere Harvester: Another silver bullet in this deck, primarily for aggro match-ups. With whir of invention, you can easily catch red aggro off guard with profitable blocks and some life-gain.

Gonti's Aether Heart: Whir of invention target, ideally on opponent’s end step when you have 1 decoction module and 1 whirler virutoso to go infinitely wide. Can also be searched out to get an extra turn in a pinch or act as a decoction module if you haven’t found one yet.

Metallic Rebuke: Only 2 copies to counter key cards. I usually play rebuke on things like Teferi, Hazoret, Phoenix, etc or to prevent opponents from dealing with my key combo pieces.

Whir of Invention: The utility in this card is incredible. Anyone who's played with Chord of Calling before can acknowledge that there is some serious power in the utility that a card like Whir of Invention has to offer. Find the missing piece of your combo, Find a silver bullet, or even set x to 0 in a pinch to find Ballista for a desperately needed decoction module trigger.

Karn, Scion of Urza: Karn is actually not as important in this deck as one might think, but can be a tremendous threat if played last or is top decked late in the game.

Aether Hub: Energy trigger and flexible mana - it’s usually best to play this land out last if you can to allow a free trigger for Fabrication Module.

Inventors' Fair: Residual life gain against aggro and finds key combo pieces if the game goes long.

Spirebluff Canal: I’m kind of torn between the fast lands and check lands.. Fast lands like spirebluff canal probably hold preference as long as aggro decks are rampant. You need to be able to play your early spells. But having mana to dump into your combo in the mid - late game is also important, and coming in to play tapped sometimes causes issues. If you have limited wildcards to spend, I’d encourage using whatever combination of Spirebluff Canal and Sulfur Falls that you can manage.

Spire of Industry: Good news, you got 4 of these for free! And they are fantastic in this deck since they allows us to more consistently cast our red spells.

Sideboard:

Shielded Aether Thief: This card most likely doesn’t belong, and should probably be treasure map instead. I want to get a little more testing in with it, though, before I just switch over to using treasure maps.

Sorcerous Spyglass: Silver bullet against a lot of the most powerful cards in the format. With 4x whir of invention, I’m seriously tempted to main board this.

Confiscation Coup: Who doesn’t want to steal a Scarab God, God-Pharaoh’s gift or some other game ending creature/artifact?

Harnessed Lightning: This deck has struggled against early Steel-leaf Champions and other Mono-Green stompy stuff. Harnessed lightning is here to hedge against that threat. I’ve only had 2 games against mono green so far, but both games were really tough for us. If my experience so far remains true in future matches, I’ll consider cutting the harness lightnings for other cards and just accept that we will likely lose the match up.

Abrade: Flexible sideboard card, and could possibly go in the main depending on what you’re seeing the most of.

Aethersphere Harvester: Extra harvester for Aggro

Magma Spray: Most efficient removal for aggro decks in the game, also exiles which is great since a lot of cards rely on doing things with the graveyard.

Negate: Let’s face it, you’ve got to be able to resolve your combo. If you’re up against an opposing control deck, you’re most likely bringing these in to make sure your key cards stick the landing.

Karn, Scion of Urza: Against midrange, control, or any attrition heavy match-up, I’d more than likely bring in the third copy of Karn.ge, control, or any attrition heavy match-up, I’d more than likely bring in the third copy of Karn.