MTG Salvation

I thinking of things like plow under or tectonic edge. What are the best cards to control lands?

Ghost Quarter is often good enough. The lands that cause you the most problems are non-basics, so GQ handles them just fine, and you can cast it at any point in the game. Others:
Blood Moon
Magus of the Moon
Fulminator Mage

I also think that Spreading Seas could be good in the right build.

Smallpox, Death Cloud and Wildfire work, although you have to build your deck around these cards.

For destroying lands you have Molten Rain and its sad cousin Stone Rain.

Annex and Mwonvuli Acid-Moss put you up one land and your opponent down one land. Crucial to the Eminent Domain deck, which also uses Wildfire.

Boomerang, Eye of Nowhere and Wipe Away can bounce lands, but their casting cost is restrictive.

Quote from izzetmage

Smallpox, Death Cloud and Wildfire work, although you have to build your deck around these cards.

For destroying lands you have Molten Rain and its sad cousin Stone Rain.

Annex and Mwonvuli Acid-Moss put you up one land and your opponent down one land. Crucial to the Eminent Domain deck, which also uses Wildfire.

Boomerang, Eye of Nowhere and Wipe Away can bounce lands, but their casting cost is restrictive.

Yes, but in Modern only a few have proven to be relevant. Deathcloud and Pox in specific builds, and I have seen Annex played a couple of times, but bouncing lands is rarely a good call, and MAM is just too expensive.

Wildfire also needs to be heavily built around.

Moonhold exists, but its not playable.

avalanche riders I think is a good card. I think it's modern legal too.
there's also acidic slime

Riders and slime are awesome. I have been having good luck with my naya lark deck

If you are utterly sick and tired of Tron, Sowing Salt is great tech.

Quote from DrWorm

Bouncing lands is rarely a good call

A bit of shameless self-promotion here. A deck with 4 Eye of Nowhere, 4 Boomerang and 4 Exhaustion fares excellently against any deck with Dark Confidant. Bounce or tap their lands and leave them unable to play anything, while Bob slowly kills them.

Bouncing shocklands is also really fun, because they lose life or tempo when they try to replay it. Given that decks with Bob are usually 3 colored (Jund or Loam), I'm sure you see where this goes.

Boom//Bust is also viable. The first half can be mitigated with fetch lands, flagstones, or Quarters/Edges.