For the first ability, the first target creature doesn't need to have a +1/+1 counter on it
If your opponent tries to kill them with removal spells, they go to exile to eventually be replayed again
If this card destroys a monster by battle and sends it to the GY: Destroy as many monsters your opponent controls as possible, and if you do, inflict 500 damage to your opponent for each monster destroyed by this effect
Souenmaten Archel (Twin Blaze Fiend Angel Archel) Souenmaten Lunael (Twin Blaze Fiend Angel Lunael) Also included are cards with effects that help a wide variety of Decks
Urza, Lord Protector is an obvious place to start, discounting all the non-creature (and non-planeswalker) spells you want in that kind of deck
You might be thinking "Just play Looters," to which I say, "Of course, but a lot of Looters need to tap!" The Mystic requires mana, but no tapping, so you can cycle as long as you have mana and a creature to discard, which can be huge in the late game