Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Counterspell

Fatal Push

Destroy target creature if it has mana value 2 or less.
Revolt — Destroy that creature if it has mana value 4 or less instead if a permanent left the battlefield under your control this turn.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Island

Polluted Delta

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Swamp

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Ashiok, Dream Render

Spells and abilities your opponents control can't cause their controller to search their library.
−1: Target player mills four cards. Then exile each opponent's graveyard.

Void Mirror

Whenever a player casts a spell, if no colored mana was spent to cast it, counter that spell.

Manasources	Probability
1	99.26%
2	92.74%
3	71.68%
4	39.09%
5	13.01%
6	2.26%
7	0.15%

Color Pip	Probability
	98.82%
	84.60%
	63.47%
	38.45%
	0.00%
	0.00%

Dimir Tempo

Instants (14)

Lands (15)

Sorceries (4)

Sideboard (3)

Probability of drawing any mana sources in your first 7 cards

Probability of drawing a mana source of a specific color pip in your first 7 cards

Mana Cost Distribution

Mana Density