True, it is a bit more like a 2 or 3 for 1 then a true sweeper. But you shouldn't discount the thing, even if in most games, it just sits there. There's gonna be games where you can do it for 2 or 1 and nab a couple mana rocks or something, and the great thing is that it can usually be tutored for should the need arise. And even if you don't activate it, it's still a land, so it still taps for mana.
In my Windgrace, I run a bunch of utility lands. Keep in mind that I run Prismatic Omen, so I can often get away with a high amount of colourless sources.
I've been trying Raging Ravine, again, as an answer to planeswalkers.
Witch's Cottage is a new card from Eldraine, but one I have been very happy with. I have several ways to sac lands and then recur them, so getting more than 1 use out of it is great. Also, it is fetchable.
Maze of Ith and Glacial Chasm are pretty great, too. Maze is essential for Windgrace, since it allows you to protect your commander. Chasm can set up some nasty situations with Crop Rotation or breaks parity on Ruric Thar, the Unbowed, and it even lessens the damage you take from your own manabase (Ancient Tomb comes to mind).
Speaking of which, Ancient Tomb and Crystal Vein are my 'Sol lands'. Especially Vein is good in Windgrace, because of obvious reasons.
A card that is very good in most Windgrace decks is Dakmor Salvage. It provides you with a constant source of lands to discard to Windgrace, as you can keep recurring it.
Blast Zone is a must, it's a boardwipe that can be recurred. It is a tad slow, but in my experience, most Windgrace decks don't lack ways to slow the game down, and it's nice to have as a red button of sorts.
Other than that, I run the standard Jund lands, but with more duals added (Tango duals and Cycle duals), because they're Mountains for Valakut purposes, along with the other cycle lands that can be discarded for one coloured mana. (Forgotten Cave, Tranquil Thicket, Barren Moor)
WiJ
Peasant 540 Cube
Field of the Dead, Dark Depths and Thespian's Stage are my wincons.
Valakut, the Molten Pinnacle often acts as removal for planeswalkers, or a boardwipe.
I've been trying Raging Ravine, again, as an answer to planeswalkers.
Witch's Cottage is a new card from Eldraine, but one I have been very happy with. I have several ways to sac lands and then recur them, so getting more than 1 use out of it is great. Also, it is fetchable.
Maze of Ith and Glacial Chasm are pretty great, too. Maze is essential for Windgrace, since it allows you to protect your commander. Chasm can set up some nasty situations with Crop Rotation or breaks parity on Ruric Thar, the Unbowed, and it even lessens the damage you take from your own manabase (Ancient Tomb comes to mind).
Speaking of which, Ancient Tomb and Crystal Vein are my 'Sol lands'. Especially Vein is good in Windgrace, because of obvious reasons.
My land destruction suite is Wasteland, Strip Mine, Tectonic Edge and Dust Bowl.
A card that is very good in most Windgrace decks is Dakmor Salvage. It provides you with a constant source of lands to discard to Windgrace, as you can keep recurring it.
Blast Zone is a must, it's a boardwipe that can be recurred. It is a tad slow, but in my experience, most Windgrace decks don't lack ways to slow the game down, and it's nice to have as a red button of sorts.
Other than that, I run the standard Jund lands, but with more duals added (Tango duals and Cycle duals), because they're Mountains for Valakut purposes, along with the other cycle lands that can be discarded for one coloured mana. (Forgotten Cave, Tranquil Thicket, Barren Moor)
Oh and Urborg, Tomb of Yawgmoth and Cabal Coffers are good, provided you run a number of tutors, since being stuck with just a Coffers is hellish.
EDIT: And obviously Bojuka Bog is a must, especially if you run Crop Rotation.
EDIT 2: Boseiju, Who Shelters All can be a consideration if you're facing lots of counterspell-based strategies.
WiJ
Peasant 540 Cube