For example, the mana value of Tavern Smasher is 4
C Common Snoww, Unlight of Dark World X DARK Level 4 [ FiendEffect ] ATK 1700 DEF 0 If this card is discarded to the GY by card effect: If it was discarded from your hand to your GY by an opponent's card effect, you can target 1 monster in your opponent's GY
Click the listing marked OPTCGSim (Swankys Version, All English Images)
Whenever Borrelsword Dragon attacks a monster, it has an effect that allows it to gain half the attack of that monster, and cause that monster to lose half of its own attack
Up to three creatures with MV 3 or less has been done at this mana cost, but putting a +1/+1 counter on each of them is pretty huge all said
Even Buried Ruin feels a little slow here, so thats taking us to five cards I wouldnt play, with a potential sixth in Command Beacon, if Im honest