msem-instigator

As an additional cost to cast this spell, sacrifice a noncreature permanent.
Search your library for a creature card with mana value equal to 1 plus the sacrificed permanent's mana value, put it onto the battlefield, then shuffle.

When Ritesinger Shaman dies, each player discards a card.

As Ritual Preparations enters, choose a color.
You don't lose unspent mana of the chosen color as steps and phases end.

As an additional cost to cast this spell, put two -1/-1 counters on a creature you control.
Draw two cards.

Bloodprice {2}{B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Create X 2/2 black Demon creature tokens, where X is one plus the number of creatures that died this turn.

Destroy all creatures with mana value 3 or less.

Menace
Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, each opponent discards a card.

Flying

When River Miscreants enters, target creature you control can't be blocked this turn.
{2}{U}: Return River Miscreants to its owner's hand. Activate only as a sorcery.

As long as your deck contains only blue and colorless cards, your minimum deck size is reduced by eight.

River's Wrath deals 2 damage to any target. If you've been dealt damage this turn, River's Wrath deals 4 damage instead.

{1}, {T}: You gain 1 life.
{2}, {T}: Tap target creature.

Choose one or both —
• Riverboat Assault deals 3 damage to target creature.
• Target creature gets +3/+3 until end of turn.

{U}, {T}: You may tap or untap another target creature.
Whenever one or more other creatures you control deal combat damage to a player, you may untap Riverchase Diver.

Harmony — Untap target permanent.
Whenever you cast an instant or sorcery spell, harmonize. (Trigger up to one harmony of one permanent you control.)

{7}{U}: Tap up to three target nonland permanents. This ability costs {2} less to activate if you control a legendary creature.

Flying
Whenever Rivha and at least two other creatures attack, exile all other attacking creatures you control. For each creature exiled this way, create a 3/3 white Angel creature token with flying that's tapped and attacking.

When Rixia, Rift Shunted enters, target creature can't be blocked this turn.
Whenever a creature you control deals combat damage to an opponent, you may aetherize it. (To aetherize, create a token that's a copy of it, then exile that token.)

As Road to Alratha enters, choose near or far.
Whenever you attack,
• Near — Creatures you control get +1/+1 until end of turn.
• Far — Put a +1/+1 counter on target creature you control. Untap it.

Search your library for up to three basic land cards, reveal those cards, shuffle, then put one of them into the battlefield tapped, one into your hand and one on top of your library.

Return target creature or land card from your graveyard to your hand.

Look at the top five cards of your library. You may reveal a land or enchantment card from among them and put it into your hand. Then put the rest on the bottom of your library in any order.

{2}, {T}: Tap target creature.

First strike
Whenever a creature dealt damage by Roadside Reaper this turn dies, you may discard a card. If you do, put a +1/+1 counter on Roadside Reaper and draw a card.

You may play this card transformed.
Trample