Archon of Emeria + Knowledge pool:
1. Whenever a player casts a spell from their hand, Knowledge Pool triggers, exiling that spell.
2. Because Archon of Emeria prevents players from casting more than one spell each turn, players cannot cast the spell permitted by Knowledge Pool, or any other spell that turn.

Infinite ETB & Colorless Mana
Emeria Shepherd+ Ashnod's Altar + Felidar Guardian:
1. Cast Felidar Guardian by paying ({3}{w})
2. Felidar Guardian enters the battlefield, blinking Plains.
3. Emeria Shepherd triggers.
4. Holding priority, activate Ashnod's Altar by sacrificing Felidar Guardian, adding ({C} magic symbol)  Magic Symbol (C)({C} magic symbol)  Magic Symbol (C).
5. Resolve the Emeria Shepherd trigger, returning Felidar Guardian from your graveyard to the battlefield.
6. Repeat from step 2.

All Basic Plains from Library to Battlefield. Potential ETB/Leave BF for # of Plains. Combo with other ETB effects for land, card-draw, destroy/exile effects, etc.
Battlefield:
Glorious Protector: ETB Exile any creatures until leaves BF
Emeria Shepherd: Landfall Return graveyard to hand or Battlefield
Solemn Simulacrum or Scampering Surveyor
Ashnod’s Altar or Phyrexian Altar
 Hold Priority:
 Glorious Protector: Choose Solemn Simulacrum.
 Exile Solemn Simulacrum.
 Ashnod’s Altar: Sacrifice Glorious Protector; add {c}{c}
 Solemn ETB. Search Basic Land.
 Emeria: Return Glorious Protector to play.
 Glorious Protector: Exile Solemn Simulacrum
 Repeat for all basic Plains.

New set: Scampering Surveyor, Unstable Glyphbridge