Mardu took some hits. Some lands rotated, but that pales in comparison to the loss of Gideon, Ally of Zendikar. Losing Thraben Inspector as an early creature that could generate an artifact was another big loss. The key to filling that gap is to find artifacts to get down early and additional 3-power creatures.
Heart of Kiran is one of the best cards in Standard. A mere 2 mana investment for something that can start attacking for 4 on turn 3, this thing can even play both offense and defense from time to time. It serves as an early artifact enabler and requires instant-speed removal (or a way to destroy artifacts) or it will punish opponents for huge chunks of life. Because four Vehicles just isn’t enough, you also have an Aethersphere Harvester to send your pilots to the skies.
Toolcraft Exemplar is best friends with Heart. Not only do your Vehicles start pumping your Exemplar as early as turn 2, but you can start combat on future turns by triggering your beginning of combat, growing the Exemplar, and then using your 1-drop to crew the Heart in the air. Again, this asks that you play a good number of artifacts, as a 1/1 for 1 is just embarrassing, but you can make that happen.
Bomat Courier is the new 1-drop of choice. In can offer card advantage as the game progresses, and it helps fuel your Exemplar by allowing the trigger to happen. In the late game, Bomat is only slightly inferior to Thraben Inspector as you won’t be able to get a chump block in addition to your card, but you’re still getting a lot for 1 mana. On an empty hand late, you can send Bomat into the red zone, let the trigger resolve, and sacrifice it after they block and before damage to get a replacement card. This also puts a creature into the graveyard, which can be extremely useful.
Scrapheap Scrounger loves full graveyards around it, and a 3-power artifact creature plays perfectly with your early curve of Exemplar and Heart. This encourages you to be incredibly aggressive since it can’t block, but a good way to crew a Heart is still incredibly useful to have around (and you can bring this back from the graveyard at instant speed to do it).
Glory-Bound Initiate gives you yet another cheap option for a 3-power creature to crew your Hearts. If left unchecked, the Initiate can start cracking in for 4 points of lifelink, making racing nearly impossible.
Pia Nalaar is a really sweet card. Not only do you get two bodies, but you get an artifact and a combined 3 power. Triggering all of your other cards is great, and the Pia + Scrounger combo to make multiple creatures unable to block can come up from time to time. Pumping your Heart in the air is just a nice bonus on top of everything else going on.
Ruin Raider is the main reason that Pias aren’t played in higher numbers. A turn-3 Ruin Raider can immediately crew a Heart, get in for 4 damage (or 7 if you had an Exemplar), and then trigger raid during your end step for an additional card. This can be a great card advantage engine, and since you’re playing a low-to-the-ground deck, you can often handle the life loss.
The top of the curve, and the only card that costs more than 3, is Hazoret. While it doesn’t play well with Ruin Raider, that’s okay. You can often pitch extra cards for damage, and if you have these giant beaters on the battlefield, things tend to be going well!
Your removal suite is top notch. Fatal Push is amazing and a great tempo play to trade up. With Grasp out of the format, killing bigger creatures isn’t the easiest thing to do. You don’t even have Murder in the format anymore! Unlicensed Disintegration is such a powerful card, and you’re likely to have an artifact in play to get that extra 3 to make it truly broken.
Mardu Vehicles has changed its main approach with Gideon gone, but it still has lots of powerful tools to close out games of Standard in a hurry.