Bygone Bishop

Flying
Whenever you cast a creature spell with mana value 3 or less, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Eternal Dragon

Flying
{3}{W}{W}: Return this card from your graveyard to your hand. Activate only during your upkeep.
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Balefire Liege

Other red creatures you control get +1/+1.
Other white creatures you control get +1/+1.
Whenever you cast a red spell, this creature deals 3 damage to target player or planeswalker.
Whenever you cast a white spell, you gain 3 life.

Eidolon of Rhetoric

Each player can't cast more than one spell each turn.

Clarion Spirit

Whenever you cast your second spell each turn, create a 1/1 white Spirit creature token with flying.

Drogskol Cavalry

Flying
Whenever another Spirit you control enters, you gain 2 life.
{3}{W}: Create a 1/1 white Spirit creature token with flying.

Hofri Ghostforge

Spirits you control get +1/+1 and have trample and haste.
Whenever another nontoken creature you control dies, exile it. If you do, create a token that's a copy of that creature, except it's a Spirit in addition to its other types and it has "When this token leaves the battlefield, return the exiled card to its owner's graveyard."

Blood Age General

{T}: Attacking Spirits get +1/+0 until end of turn.

Bell Borca, Spectral Sergeant

Note the mana value of each card as it's put into exile.
Bell Borca's power is equal to the greatest number noted for it this turn.
At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.