Activate Ashnod's Altar by sacrificing Spark Double, adding {C}{C}.
When Spark Double dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
As Spark Double enters the battlefield, choose to have it enter the battlefield as a copy of Glen Elendra Archmage with a +1/+1 counter on it.
Repeat.

Infinite colorless mana

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Spark Double

Glen Elendra Archmage

Ashnod's Altar

Activate Ashnod's Altar by sacrificing Glen Elendra Archmage, adding {C}{C}.
Glen Elendra Archmage dies, triggering its persist ability, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Glen Elendra Archmage enters the battlefield, triggering Denry Klin, putting a +1/+1 counter on Glen Elendra Archmage.
Repeat.

Denry Klin, Editor in Chief

Activate Zameck Guildmage's first ability by paying {G}{U}, causing each creature you control to enter the battlefield with an additional +1/+1 counter this turn.
Activate Ashnod's Altar by sacrificing Glen Elendra Archmage, adding {C}{C}.
Glen Elendra Archmage dies, triggering its persist ability, returning it from your graveyard to the battlefield with no -1/-1 counters due to Zameck Guildmage.
Repeat from step 2.

Zameck Guildmage

Activate Zameck Guildmage's first ability by paying {G}{U}, causing each creature you control to enter the battlefield with an additional +1/+1 counter this turn.
Activate Phyrexian Altar by sacrificing Glen Elendra Archmage, adding one mana of any color.
When Glen Elendra Archmage dies, it triggers its persist ability, returning it from your graveyard to the battlefield with a -1/-1 counter and a +1/+1 counter on it.
The two counters are removed from Glen Elendra  as a state-based action.
Repeat from step 2 any number of times.
Once you have infinite mana, you amy activate Zameck Guildmage's abilities any number of times.

Infinite +1/+1 counters on certain creatures

Infinite card draw

Infinite colored mana

Infinite draw triggers

Phyrexian Altar

Activate Phyrexian Altar by sacrificing Glen Elendra Archmage, adding one mana of any color.
Glen Elendra Archmage dies, triggering its persist ability, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Glen Elendra Archmage enters the battlefield, triggering Intruder Alarm, untapping all creatures.
Activate Scholar of New Horizons by tapping it and removing the -1/-1 counter from Glen Elendra Archmage, causing you to search your library for a Plains card and either put it onto the battlefield or put it into your hand.
Repeat.

Infinite mana creatures you control can produce

Infinite untap of creatures

Put all Plains cards from your libary into your hand

Scholar of New Horizons

Intruder Alarm

Activate Ashnod's Altar by sacrificing Glen Elendra Archmage, adding {C}{C}.
Glen Elendra Archmage dies, triggering its persist ability, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Glen Elendra Archmage enters the battlefield, triggering Intruder Alarm, untapping all creatures.
Activate Scholar of New Horizons by tapping it and removing the -1/-1 counter from Glen Elendra Archmage, causing you to search your library for a Plains card and either put it onto the battlefield or put it into your hand.
Repeat.

Combos with "Glen Elendra Archmage"