This is my first attempt (now with many edits) at reformatting B/G Explore for Rivals of Ixalan Standard, and it's with the combination of Animation Module, Path of Discovery, and Wildgrowth Walker! I learned about this combo by reading one of @ecocd's tweets, and the build is based on SBMTGDev's original budget explore list and his later post of exactly this type of deck.
The Combo
The key combo is in getting both Animation Module and Path of Discovery onto the board. Then, whenever a creature explores and receives a +1/+1 counter, which they will do upon entering the battlefield with Path of Discovery's effect, you can pay 1 mana to create a Servo; that Servo will explore due to Path of Discovery, potentially receiving a +1/+1 counter and starting the process anew. If you have a Wildgrowth Walker as well, it guarantees that every new Servo will cause the Walker to get a +1/+1 counter, thus ensuring the continued production of Servo tokens until you're out of mana, if you so desire. The combo is incredible for going wide, buffing up Wildgrowth Walker, and gaining a bunch of life. It is, however, weak to sweepers, and can only happen later in the game because Path of Discovery costs 4 mana.
Card Choices
I changed the 3 copies of Deadeye Tracker in the main to three copies in the side to make room for Tomb Robber, which, admittedly, has a nice effect to get rid of useless lands in hand (although any extra lands make Animation Module combos last longer). Jadelight Ranger is a very strong explore card that I'm choosing to play over copies of Ixalli's Diviner and Tishana's Wayfinder in this build because it seems objectively better than both of them. Winding Constrictor is included to make the addition of +1/+1 counters from Explore, Wildgrowth Walker, and Animation Module even more oppressive. Tomb Robber also combos nicely with Liliana to revive creatures I discard. Explore does too. In general, I agree that she's a smart planeswalker to play in the deck.
Balancing the Deck
The creature count is a little lower than was typical in Ixalan standard Black/Green explore builds. This is to make room for Path of Discovery while maintaining access to Blossoming Defense, the only real main deck protection for buffed up Wildgrowth Walkers, and Enter the Unknown, which gives us powerful ramp to allow for a slightly earlier Path of Discovery play (which is important, since it has the potential to both buff our creatures and draw into more lands to use with Animation Module). Enter the Unknown acts like another explore creature on the draw, with the ability to buff Wildgrowth Walker directly and let us play another land. Considering how cheap it is mana wise, there isn't a reason not to play 3 or 4. The problem I have is that this makes things a little spell-heavy, and that the deck leans really heavily towards green over black.
On that note; the reasons why I chose to keep black are twofold. First, I wanted to maintain access to Deadeye Tracker (In the side) and Tomb Robber. Secondly, the sideboard and removal options seem much stronger in black. Black mana, for example, allows me to play Never // Return, where Return has the potential to start the Explore chain with Path of Discovery and Animation Module by creating a creature, and Fatal Push/Vraska's Contempt, both of which help prevent us from getting blown out. Green still supports very nice cards, though. Champion's Intervention can protect a board with a great number of Servos and valuable +1/+1 counters against sweepers, and green cards like Thrashing Brontodon, Slice in Twain, or the newly re-released Naturalize help against GPG and other Artifact/Enchantment heavy decks.
Other Considerations
Fatal Push is a really solid card that makes this deck playable against Aggro. However, it could theoretically be replaced by Never // Return to clear more creatures (big stuff that control plays as finishers, for example) and abuse the ability to create zombies. As of now, I would mainly consider 1 copy of Never // Return and one copy of Vraska's Contempt in the main with the four Fatal Push, since Fatal Push ameliorates the aggro matchup so much.
The Naturalize slot could also be Thrashing Brontodon or Slice in Twain. Naturalize runs at a lower cost and requires less green mana and Brontodon's effect comes in on a body, which could be useful with Path of Discovery. Brontodon, however, risks getting removed if you play it on three mana before you can ever use its effect--if you really want to use it to remove an enchantment, you have to play it with 4 mana up anyway, which makes it just as expensive as Slice in Twain without the draw a card effect. Slice in Twain's draw effect is of course fairly strong, which is why it's included, but the 4 CMC and requirement of two green mana may be excessive when trying to handle combos that could become problematic as early as turn 4.
I would appreciate any advice that you can offer! Again, thanks are due to SBMTGDev for the original shell and @ecocd on Twitter for the combo idea.
