Well, the full spoiler is here, and while there may not be a ton of financial gems in the last wave of cards, there are some relevant cards, and a few uncommons that may be worth an uncommonly high amount of money. Let's dive in.

Timely Hordemate

This is absolutely cube-playable. It's a great effect albeit a clunky one forcing you to try and trigger raid with white creatures in a cube with probably 0 other mardu cards. Still, white creatures attack and this can rebuy a good one like Burrenton Forge-Tender or Stoneforge Mystic. I bet someone opens a foil at the prerelease. Go home with it.

Sultai Scavenger

A literal delver? A 3/3 flier for 1 mana is nothing to sneeze at, as evidenced by Delver of Secrets and this delver doesn't need to trigger anything to flip. For less effort than it takes to make Nimble Mongoose hexproof you can get this guy out and swinging. Would you rather play Tombstalker? Not everyone agrees, and with the odds that this could impact Legacy being non-zero, I would see if you can't get a few cheap foils before the price does whatever it will do. This is all upside.

Burn Away

This is a potential Sultai-ruiner and I would grab as many of these in draft chaff as you can. If Sultai starts to get there, this may be a good tool for dealing with it. Do we want to pay 5 mana rather than just use Tormod's Crypt? We don't need to be right about that, we just need to be prepared for the metagame to do what it will do.

Tormenting Voice

Discarding first isn't ideal, but effects like this are good enablers. I'd watch and see what this does, and try and trade for foils before the price is established.

Archer's Parapet

No financial impact here, but be prepared to rage scoop to this if you play 2-headed giant.

Longshot Squad

Experiment Kraj type decks may want this.

Seek the Horizon

This is a card that sees play in EDH and foils of this are going to induce boners. Trade for every foil of this at the prerelease. I could see it being a couple of bucks and you might get a premium just because it looks so much better than previous versions. RTR foil STH is $0.50 and I am happy to trade for these at that price because I think the art gives it enough upside. I'm not in with cash, though.

Death Frenzy

Can't decide if this is too narrow for EDH or too hilarious when you pants a token deck. I guess you don't need a second, weaker Massacre Wurm in the end. Still funny with your own tokens and a fecundity, but so is Decree of Pain.

Warden of the Eye

Could be the next Archeomancer, although he's in awkward colors.

Altar of the Brood

This is likely not as good as it appears to me prima facie but I think this can really grind people down. I can't imagine in which deck or which situation, but something as grindy as this has to get there, doesn't it? In any case, I imagine this is a bulk rare to begin with, which is all we can ask of cards with potential.

Tomb of the Spirit Dragon

UGIN CUNFIRMD!!!!!!!!!!!11eleven

Monastery Swiftspear

This card. I can't decide if it's a half-assed Goblin Guide or a half-assed Chandra's Spitfire but I know that I love it with my whole ass. It doesn't have a drawback, can outdamage goblin guide if you're burning aggressively and isn't $20 or whatever. This is a card to watch. All of my monored playing friends have taken notice already.

Hordeling Outburst

That's so many tokens for 3 mana. That is so, so many tokens. I can't believe how many tokens it is. I don't see "1 more mana than Dragon Fodder for 1 more token" I see "6 damage from Purphoros for 3 mana and one card". So many tokens!