I like big butts, and I cannot lie... With this deck, the best offense is a good defense, utilizing Doran, the Siege Tower or Assault Formation to turn your cheap, defensive creatures into offensive powerhouses.

Doran, the Siege Tower, Treefolk Harbinger, Spellskite, and Nyx-Fleece Ram all attack without needing Assault Formation to remove defender. Wall of Omens, Jeskai Barricade , and Tree of Redemption need Assault Formation out in order to lose defender.

Collected Company is nice here because it not only hits all but one of our creatures (poor Tree of Redemption gets left out), it also hits one of our enablers, Doran, the Siege Tower.

Of course, resiliency is important. Spellskite is very commonly played in Modern, but as a sideboard offering. Here, we get to maindeck it as an effective 4/4 for 2, and we get to use its ability to protect our key players. Also, flashing in Jeskai Barricade (another effective 4/4 for 2) to bounce back your creature that's been targeted for death.

Even if you don't have Doran, the Siege Tower or Assault Formation, you still have ways to get solid threats onto the board. Kin-Tree Invocation + Tree of Redemption is bonkers, giving you a 13/13 creature token that's not reliant on any other card in order to attack. Even if you don't have Tree of Redemption out, it can still provide solid threats ranging from 3/3 all the way to 5/5 for only two mana.

Finally, Tower Defense serves as a great, out of nowhere trick that works as a surprise finisher.

Overall, this is a fun core to play with. No sideboard recommendations, as that's preferential and dependent on the meta you're playing in. This is more of a 'core' with modifications encouraged based on needs.