Blinding-Sword KnightXXWW
Creature — Knight (U)
First strike
Blinding-Sword Knight enters the battlefield with X light counters on it.
Whenever Blinding-Sword Knight attacks, for each light counter on it, you may tap target creature.
2/2
Meddling OupheX1UU
Creature — Ouphe Wizard (U)
Meddling Ouphe enters the battlefield with X meddle counters on it. UU, Sacrifice Meddling Ouphe: Counter target spell with converted mana cost less than or equal to the number of meddle counters on Meddling Ouphe.
2/2
Pactform DemonX3BB
Creature — Demon (U)
Pactform Demon enters the battlefield with X pact counters on it.
When Pactform Demon dies, each opponent sacrifices a creature for each pact counter on Pactform Demon.
5/5
Combustion ElementalX1RR
Creature — Elemental (U)
Combustion Elemental enters the battlefield with X fuel counters on it.
When Combustion Elemental dies, it deals damage to target creature or player equal to the number of fuel counters on it.
3/2
Everflow HivemasterX2GG
Creature — Insect (U)
Everflow Hivemaster enters the battlefield with X swarm counters on it.
Whenever Everflow Hivemaster attacks, put a 1/1 green Insect creature token onto the battlefield tapped and attacking for each swarm counter on it.
4/4
Cloudcairn Runestone(2/W)(2/U)
Artifact (C)
Cloudcairn Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, draw a card. T: Add W or U to your mana pool.
Garamor Runestone(2/R)(2/G)
Artifact (C)
Garamor Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, put a 2/1 red and green Elemental creature token onto the battlefield. T: Add R or G to your mana pool.
Kolbrek Runestone(2/B)(2/R)
Artifact (C)
Kolbrek Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, target creature can’t block this turn. T: Add B or R to your mana pool.
Mahanti Runestone(2/G)(2/W)
Artifact (C)
Mahanti Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, you may put a +1/+1 counter on target creature. T: Add G or W to your mana pool.
Umbric Runestone(2/U)(2/B)
Artifact (C)
Umbric Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, exile the top four cards of target player’s library. T: Add U or B to your mana pool.
The last BR and WG seem underwhelming compared to the first two.
And I'm uncomfortable with the thought of a milling spell at common. While in constructed the exile 4 is just an annoyance and does next to nothing in constructed, you can draft a decent amount of them in limited, and limited has a smaller library, and unlike other mill spells these have use other than milling (like glimpse the unthinkable, mind sculpt, or tome scour).
Maybe "if you spend at least three" on the cycle. I dunno, that might be OP. I think you could make GW two counters (on the same creature, two creatures, or either?) and the BR one could be -1/-1 to target creature (which might accomplish the same thing- demanding more careful blocking) as well as removal for chumps.
Blinding-Sword Knight XXWW
Creature — Knight (U)
First strike
Blinding-Sword Knight enters the battlefield with X light counters on it.
Whenever Blinding-Sword Knight attacks, for each light counter on it, you may tap target creature.
2/2
Meddling Ouphe X1UU
Creature — Ouphe Wizard (U)
Meddling Ouphe enters the battlefield with X meddle counters on it.
UU, Sacrifice Meddling Ouphe: Counter target spell with converted mana cost less than or equal to the number of meddle counters on Meddling Ouphe.
2/2
Pactform Demon X3BB
Creature — Demon (U)
Pactform Demon enters the battlefield with X pact counters on it.
When Pactform Demon dies, each opponent sacrifices a creature for each pact counter on Pactform Demon.
5/5
Combustion Elemental X1RR
Creature — Elemental (U)
Combustion Elemental enters the battlefield with X fuel counters on it.
When Combustion Elemental dies, it deals damage to target creature or player equal to the number of fuel counters on it.
3/2
Everflow Hivemaster X2GG
Creature — Insect (U)
Everflow Hivemaster enters the battlefield with X swarm counters on it.
Whenever Everflow Hivemaster attacks, put a 1/1 green Insect creature token onto the battlefield tapped and attacking for each swarm counter on it.
4/4
Cloudcairn Runestone (2/W)(2/U)
Artifact (C)
Cloudcairn Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, draw a card.
T: Add W or U to your mana pool.
Garamor Runestone (2/R)(2/G)
Artifact (C)
Garamor Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, put a 2/1 red and green Elemental creature token onto the battlefield.
T: Add R or G to your mana pool.
Kolbrek Runestone (2/B)(2/R)
Artifact (C)
Kolbrek Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, target creature can’t block this turn.
T: Add B or R to your mana pool.
Mahanti Runestone (2/G)(2/W)
Artifact (C)
Mahanti Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, you may put a +1/+1 counter on target creature.
T: Add G or W to your mana pool.
Umbric Runestone (2/U)(2/B)
Artifact (C)
Umbric Runestone enters the battlefield tapped. When it does, if you spent at least four mana to cast it, exile the top four cards of target player’s library.
T: Add U or B to your mana pool.
And I'm uncomfortable with the thought of a milling spell at common. While in constructed the exile 4 is just an annoyance and does next to nothing in constructed, you can draft a decent amount of them in limited, and limited has a smaller library, and unlike other mill spells these have use other than milling (like glimpse the unthinkable, mind sculpt, or tome scour).
"Sometimes, the situation is outracing a threat, sometimes it's ignoring it, and sometimes it involves sideboarding in 4x Hope//Pray." --Doug Linn
My pet, really super tentantive, in development, 40-man format- Star Team!
Modern-
RWG"Frigga" (Allies)GWR
Standard-
"Kendra" (RabbleRed)
EDH-
WUR Zedruu ControlRUW
RUG Riku GUR
BGW Ghave WBG
RWB Kaalia BWR
CUBE-
Khans of Tarkir Procedural Cube