Out of the creatures, I like Thermo-Alchemist as an effective third iteration of the two main cards from the deck, Night Market Lookout and Spireside Infiltrator
When The Locust God dies, return it to its owner's hand at the beginning of the next end step
Fetch lands are incredibly good because they fix your mana , can get basic or dual lands , generate two landfall triggers , and provide a shuffle effect
On the other hand, if the build is centered around artifacts, Etherium Sculptor makes things run smoother, and you can use some key combinations like Nevinyrral's Disk + Darksteel Forge to get a one-sided board wipe or rely on the Thopter Foundry + Sword of the Meek to outvalue your opponents
Now I may be talking down the importance of actually closing the game, but the reality is that it does add real percentage points to control decks