Enters-the-battlefield ability of anything from Mulldrifter to Mycosynth Wellspring
Some good ones I found on a cursory search are Crash Through if you really need Balduvian's draw, or Brute Strength, Built to Smash, Invigorated Rampage, Ride Down, Run Amok, Rush of Adrenaline and Temur Battle Rage are all fairly inexpensive (both in terms of CMC and market price on the cards) spells that will give your creatures a boost, destroy blocking creatures (with regard to Ride Down), and give trample
C Common Chewbone X EARTH Level 3 [ ZombieFlipEffect ] ATK 300 DEF 300 FLIP: Special Summon 3 "Chewbone Jr
Yes, it feeds into all these other loops
Players must recognize the purpose of their purchase
Update June 26, 11:15am CT : All MTG Lord of the Ring card prices were updated following the global launch