It can pump our commander to massive proportions and the trample it gives the creature ensures we get damage through chump blockers
The color scheme is very pleasing and the art style separates it from others that verge on realism when it comes to backgrounds
Nowadays the bar is a little higher, and War Monk hasn't really seen competitive play in years, but the pancake spinner is still a hardworking classic

Bot Adventurer's Airship Aerial Doombot Aerial Surveyor Aerial Toastmaster Aeronaut's Wings Aesthir Glider Aetherjacket Aethersphere Harvester Aetherwing, Golden-Scale Flagship Agent's Toolkit Air Response Unit Akroma's Memorial Al-abara's Carpet Andril, Flame of the West Angel of the Ruins Angel's Tomb Angelic Armaments Angelic Rocket Anvilwrought Raptor Applied Aeronautics Arachnoid Arcanist's Owl Arcbound Condor Arcbound Stinger Arcbound Whelp Argivian Avenger Artificer's Dragon Atarka Monument Atmospheric Greenhouse Atraxa's Skitterfang Auxiliary Boosters Avacyn's Collar Avengers Quinjet Azorius Keyrune Balamb Garden, Airborne Baleful Strix Balloon Stand Balloon Stand Balloon Stand Balloon Stand Barbed Spike Basilica Skullbomb Biblioplex Assistant Bladed Pinions Bladegriff Prototype Blitzwing, Adaptive Assailant Bloodsoaked Altar Bottle of Suleiman Boulderborn Dragon Bow of Nylea Brass Gnat Breya's Apprentice Breya, Etherium Shaper Broadcast Rambler Brotherhood Vertibird Buzz Bots Camera Launcher Canoptek Scarab Swarm Canoptek Spyder Cargo Ship Celebr-8000 Celestial Armor Cephalopod Sentry Chardalyn Dragon Chariot of the Sun Chimeric Sphere Chipper Chopper Chivalrous Chevalier Chrome Courier Chronomancer Clay Pigeon

Two or more creatures you control must attack the same player in order for Landroval, Horizon Witness's ability to trigger
There are likely other great companions for it, but one option shows up in the set: Xerneas