In case you somehow missed it, we now have a confirmed new "Spell Lands" cycle at Common in Battle for Zendikar:
Alex Ullman has an excellent review of this new cycle over at GatheringMagic.com, and I highly recommend you check it out. He seems cautiously optimistic about these cards seeing some play in Classic Pauper, especially thanks to the fact that Crop Rotation creates the possibility of turning these into Instant speed tricks. But what about in Standard Pauper?
Both Sandstone Bridge and Looming Spires are fairly good value, providing not only a small boost to Power and Toughness but either Vigilance or First Strike as well. However, since Red and White both tend to be fairly aggressive, the fact that these enter the battlefield tapped is not to be ignored. Between Evolving Wilds and the Common Dual Lands that enter tapped, we already have a glut of lands that aren't available to use when they come into play. It will take some significant testing to figure out how many of these such decks can afford to slot in.
Skyline Cascade is a perfect fit for a Blue or Izzet tempo deck looking to use bounce and other tap effects to keep opposing creatures at bay long enough to finish off an opponent. Keep in mind that it doesn't actually tap the targeted creature; it merely keeps it tapped for an additional round. So this won't function as much of a combat trick, since your opponent will already know that the creature will be tapped on your turn. Still, for a spell effect that you get 'for free' from a Land, this is still good value.
Mortuary Mire is a bit of a puzzle to me still. Reclaim will always be a terrible card, since you're both giving up a card and your next draw to get a single card back into your hand from your graveyard. But when you're getting that effect on a Land, the cost of doing so is significantly reduced. Still, would it really have been too good to allow you to return a creature to your hand instead? As is, the creature you are returning needs to be among the best in your deck to make this an attractive option.
And as for Fertile Thicket...I think I'll save that for next time. :)