Variant of Dimir Delver. Control the game with counterspells and card advantage. The win can happen either slowly with Delver/Triton Shorestalker or quickly with Gurmag when it comes in.

Card advantage accrues from cantrips, card drawing spells, and most importantly, card draw when my evasive creatures deal damage.

Current version is working surprisingly well, but could be better if it took advantage of all the land. I should either:

1) replace many lands with terramorphic, Evolving Wilds, and/or cycle lands in or to effectively shrink the deck

2) make better use of black, by having some really good high cost black "finisher" spells or removal (doom blade, unmake, etc. or maybe some of the higher cost ones that offer extras))

3) high cost finisher spell (not necessarily blue - could be another color if I change all my lands to another color with Terraformer or Elsewhere Flask which black needs for its effective finisher cards, or maybe just generate 1 red mana for access to some of the red finishers like Kaervek's Torch)

If I do #1 above and put in a couple swamps, then I get access to doom blades and other removal options. Unearth is also worth considering, as having Delver come back over and over could be good.

Cards that pique my interest:

Stiched Drake: Delver dies. So bring in Stitched Drake.

Calcite Snapper: 1/4 can't lightning bolt this thing yet it can switch to do 4 damage every time a land comes in, and thus has good synergy with Gush, Dimir Aqueduct, and the land-heavy deck.

Chained Throatseeker: 5/5 with infect means this only needs to swing twice - but I somehow have to get a poison counter on the player first before playing this. Works especially well with Blighted Agent, Phyresis, and Tainted Strike. Other possible things to work with are Blackcleave Goblin, Contagious Nim, Corpse Cur, Flensermite, Ichorclaw Myr, Pestilent Souleater, Phyresis, Phyrexian Digester, Plague Stinger, Toxic Nim, and Vector Asp

Sivitri Scarzam: All other blue-only big common creatures have way-too-big drawbacks. This has 1 black in cost and at 6/4 does damage faster the Delver. Of course Gurmag is better in many ways but if I need to preserve my graveyard for some other use, or just don't have much there, then this is next best.

Dross Crocodile (or rotting Fensake): 5/1 for cost of only 4. If I can counter everything and thus keep it on the battlefield, then this is pretty nasty.

Terrus Worm is expensive but has scavange.

Twisted Abomination has regenerate

Adventuring Gear - bounce lands and gush insure many lands coming in.

Mysteries of the Deep is the only way to get a 3 card blue draw in Pauper (requires land entering the battlefield)

Ior Ruin Expedition - 2 cards for cheap as long as land keeps coming in

Soul Stair Expedtion - 2 creatures come back from graveyard as long as land keeps coming in

Bog Wreckage - maybe this makes more sense than the Dimir Acqueducts. I could then have a couple of red finisher spells (i.e. Kaervek's Torch).