Quote from IcecreamMan80Flash of Forbearance 2WR
Target creature, and all other creatures with power less than or equal to that
creatures power cannot attack or block this turn.
Quote from OunceOfGoldOozemaster 2GG
Creature - Human Druid
Creature spells you play cost less to play.
1G, sacrifice a non-Ooze creature: Put an X/X green Ooze creature token onto the battlefield.
Quote from ryzorzSoldiers of Ugin's Flame 1RRR
Creature - Human Soldier
~ is colorless.
Protection from red
X,T: ~ deals X damage to each creature. Spend only red mana to activate this ability.
Quote from Voila!Placeholder - Attack Filter
Creatures you control can't attack.
x, Sacrifice a creature: You may put a creature card from your hand onto the battlefield tapped and attacking. Activate this ability only during your declare attackers step.
Quote from GetItWrongNot sure, but I don't think so, mainly because of the n-for-one possibility if it gets killed. I don't really count the +1/+1 counters as upside because your opponent controls how many it gets.
Quote from ryzorzYes 1RG
Spells, Triggered abilities, and Activated abilities you control gain "This Spell or Ability can not be countered by spells or abilities".