I'll post the preview cards from Izzet vs. Golgari tomorrow, but tonight the Magic Player's Championship and online copies of Izzet vs. Golgari seems to have brought some interesting developments.
First off, the link that's about to follow has artwork for 4-5 cycles of Guild-based cards among both Return to Ravnica and Gatecrash. http://imgur.com/a/T9wjh
While there are no specific names (except for already-spoiled cards from Izzet vs. Golgari), it does break down to the following (in order):
10 Guildmages (sorry, no reprints from the original Ravnica block. These Guildmages are 2-color, non-hybrid 2/2's with 2 multi-color abilities.)
10 Guild Leaders (yes, you see Isperia, what seems to be a Ghost Council, and Jarad)
10 Signets (so yes, we're getting Simic Signet, Gruul Signet, Orzhov Signet, etc. all back in Standard for 2 years!)
10 "Charms" (from the spoiled Izzet Charm art last night...which I'll post tomorrow. lol!)
10 "Death to [Guild]" (which isn't noted as such, but Evan Erwin's Twitter calls it that: https://twitter.com/misterorange/status/241000829899919361)
As well, some interesting artwork came up while Featured Matches from the Magic Player's Championship were airing online. Look at these images (from MTGSalvation.com) and see what you think:
Hmm...I see a fountain sitting by itself and an anvil with molten something pouring out of it.
Kind of sounds like a Hallowed Fountain and a Sacred Foundry, eh? ;)
While it doesn't prove the existence of "Shocklands" (lands that enter the battlefield tapped unless you pay 2 life, like a self-Shock), keep these in mind...
1) WotC has said time and time again that new players don't like having life loss tacked onto their lands. Well...Shocklands aren't meant for the new player, they're meant for the strategic player who can either make back the 2-life investment or don't mind taking 2 life payment for having a land with 2 land types enter in. And Expansion sets aren't the place to be picking up new players, really...
2) Farseek's reprinting, along with new cards like Liliana's Shade and Gem of Becoming, show an interesting pattern...these cards say to search for "a Mountain card" or "a Swamp card" but not a "basic Swamp card", for example. Well...Shocklands have basic land types on them, meaning Farseek, Liliana's Shade, and Gem of Becoming can each search out, say, a Watery Grave.
3) WotC has had plans on reprinting these babies since when they came out. That's why they had fairly generic names such as "Watery Grave". You could set this on Zendikar, for example, in the swamps of Nephalia, so "Watery Grave" is not a plane-specific location. Their original intent was to put them into Core Sets, or at least that was the idea (to replace "Painlands" [Lands where you tapped for 1 Colorless mana OR got 1 of 2 colors for a 1-life payment] supposedly), and Core Sets at the time needed non-planar names moving forward. Instead, we got lands like Rootbound Crag as a direct result of Issue #1.
4) Wizards of the Coast has also said since Modern started as a format that they want to reprint staples at easier-to-get venues. Shocklands are just as helpful there as the original Dual Lands are for Legacy, so this would be a perfect avenue to reprint them: in a set that returns to where they came from!
Granted, it's all circumstantial evidence, but the timing is either all to coincidental or one big trolling. lol!
Finally, there are pictures of the supposedly-fake-but-could-be-real Rootborn Defenses being signed by the Return to Ravnica design team. I doubt they'd sign a completely fake card, so Rootborn Defenses is real.
This confirms now 3 new keywords for the Guilds in Return to Ravnica:
SELESNYA: Populate (To populate, put a token onto the battlefield that's a copy of a creature token you control.) (works with Ravnica: City of Guilds' Convoke, which lets you effectively treat creatures as mana)
GOLGARI: Scavenge [COST] ([COST], exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.) (works with Ravnica: City of Guilds' Dredge, which let you get back cards by replacing your draw with milling yourself for a certain amount of cards. If a Scavenge card ends up in your graveyard from Dredging, well...)
IZZET: Overload [COST] (You may cast this spell for its overload cost. If you do, change its test by replacing all instance of "target" with "each".) (Kind of works similarly to Guildpact's Replicate, which let you make copies of the spell for any number of times you could pay the Replicate cost [usually equal to the original mana cost])
We do not know what Azorius and Gruul's will be, but their originals were Forecast (on the upkeep, you could reveal the card from your hand and pay the Forecast cost to get a certain effect) and Bloodthirst (if this creature comes into play after an opponent took damage, you put a certain number of +1/+1 counters on it).
That's all I have time for tonight, but tomorrow I'll be back with a more thorough card update of what we know about Return to Ravnica, as well as some storyline links for you. :)