This commander plays much better if you use the mana reduction to make 2-3 mana interaction spells cost a single mana rather than getting a discount on bigger cards like Breach the Multiverse
If youre curious to see what else the set offers, you can check out the full catalog
Build the deck right, and youre dropping cosmic horror for free while your opponents are still casting mana rocks

$59.99 Azusa, Lost but Seeking (0015 - Princess Sarah) Final Fantasy Through the Ages $19.99 Winota, Joiner of Forces (0019 - Bartz Klauser) Final Fantasy Through the Ages $12.99 Traxos, Scourge of Kroog (0020 - Giant of Babil) Final Fantasy Through the Ages $29.99 Kenrith, the Returned King (0023 - Noctis Lucis Caelum) Final Fantasy Through the Ages $10.99 Bruse Tarl, Boorish Herder (0050 - Hugo Kupka) Final Fantasy Through the Ages $32.99 Sram, Senior Edificer (0003 - Firion, Swordmaster) Final Fantasy Through the Ages $54.99 Dark Ritual (0008 - Darkness of Eternity) Final Fantasy Through the Ages $32.99 Adeline, Resplendent Cathar (0001 - Hero of Light) Final Fantasy Through the Ages $79.99 Vial Smasher the Fierce (0059 - Clive Rosfield) Final Fantasy Through the Ages $37.99 Gix, Yawgmoth Praetor (0035 - The Shadow Lord) Final Fantasy Through the Ages $11.99 Mangara, the Diplomat (0025 - Minwu, Rebellion Strategist) Final Fantasy Through the Ages $109.99 Nyxbloom Ancient (0016 - The Cloudsea Djinn) Final Fantasy Through the Ages 0 results found

Every single one of them was mono-colorless not because of the spells, but the lands
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions (such as that of Stormwing Entity)