It is important to remember that it triggers on the announcement of a spell so you
draw the cards and then counter.

Standstill is already proving to be a very strong choice for card drawing in a deck
that can quickly lay out a few threats and protect its position. This translates into card advantage
with the proper cards.
I have been experimenting with a Standard version:

4 Nimble Mongoose
4 Blurred Mongoose
4 Wild Mongrel
4 Gaeas Skyfolk
4 Mystic Snake

4 Aether Burst
4 Standstill
3 Memory Lapse
3 Syncopate
2 Rushing River

10 Islands
10 Forests
4 Yavimaya Coast

The sideboard
3 Gainsay
3 Divert.
3 Leaf Dancers,
3 Dodecapod
2 Jungle Barriers
1 Rushing River

I am able to gain enormous card advantage against most decks with this build.

In Type 1 but the rebel engine has potential when coupled with Standstill. WW can race with
almost any aggro deck. It can race Sligh, Black and Stompy in Type 1 with the addition of
Standstill and it finds an answer to control in order to be consistent. Standstillis p[erfect for the rebel engine.
A budget version would be playable but a good Type 1 deck is helped by some P9.

This deck has solutions.

4 Savannah Lions
4 Ramosian Sergeant
4 Steadfast Guard
4 Fresh Volunteer
4 Meddling Mage

4 Standstill
4 Land Tax
2 Seal of Cleansing
2 Crusade
2 Null Rod
2 Swords to Plowshares
1 Balance
1 Ancestral Recall
1 Time Walk

8 Plains
4 Tundra
4 Adarkar
2 Wasteland
1 Mox Pearl
1 Mox Saphire
1 Black Lotus
1 Strip Mine

SB
4 Extract
3 Psi Blasts
3 Sanctimony
2 Lingering Mirage
2 Seal of Cleansing
1 Tornod’s Crypt

The sideboard is built to have a few more answers. Extract is no Cap
but in a tempo deck it can remove enough problems that the Mages will
lock the game down.
The Psi Blasts are finishers that can be sided in if you need to race.
Sanctimony will ensure that you out race Sligh.
Lingering Mirage is just tech against Academy and a few other nasty lands.
Seals and Crypt are more solutions for Oath and Keeper.

I also like its application to a solid B/u build. This deck can play a threat and
Standstill very early. It then has the utility to disrupt or counter a few spells long
enough for the win. I had thought about incorporating a few Shadowmage Infiltrators for
an even more control but it is still in its infancy and needs more testing.

Creatures: 12
4 x Phyrexian Scuta
4 x Serendib Efreet
4 x Hypnotic Specter

Card Drawers: 6
4 x Standstill
1 x Necropotence
1 x Ancestral Recall

Utility: 16
4 x Mana Drain
4 x Duress
4 x Hymn to Tourach
1x Time Walk
1 x Demonic Tutor
1 x Demonic Consultation
1 x Yawgmoth´s Will

Mana:
4 x Dark Ritual
1 x Sol Ring
5 x Swamp
4 x Underground Sea
4 x Underground River
3 x Mishra´s Factory
2 x City of Pain
2 x Island
1 x Strip Mine

SB:
4 x Phyrexian Negator
3 x Powder Keg
2 x Perish
2 x Teferi's Response
2 x Dystopia
2 x Diabolic Edict

The other deck that can benefit from Standstill is an Extended or Type 1 Oath. I also like
Pedantic Learning in the deck.

Pedantic Learning
UU, Enchantment, Odyssey Rare
Whenever a land card is put into your graveyard from your library, you may pay 1. If you do, draw a card.
Even the trivial can inspire.
Illus. Heather Hudson
Between these two cards you can generate enormous card advantage with
Oath in play.

So that’s it for now and remember:

Magic is after all a game. Have fun.