An interesting aspect of Flesh and Blood is the recycling of cards to use as resources when bringing other cards into play
Magmortar can be obtained from Space-Time Smackdown: Palkia pack in the Space-Time Smackdown set
I will say in the very beginning, I had to know how things worked because I didnt understand how the CPMs worked and everything, so it was kind of learning over the years how all of that works
Milling sounds attractive because you get to "destroy" many of your opponents cards at once
Ramp: Sakura-Tribe Elder, Rampant Growth, Farseek, Nature's Lore, Kodama's Reach, Explosive Vegetation, Skyshroud Claim, Tempt with Discovery, Urza's Incubator, Sword of Feast and Famine Card Advantage: Puresteel Paladin, Sram, Senior Edificer, Stone Haven Outfitter, Mask of Memory, Sword of Fire and Ice, Rishkar's Expertise, Hunter's Insight, Life's Legacy, Greater Good, Lifecrafter's Bestiary, Sylvan Library Protection: Heroic Intervention, Champion's Helm, Nim Deathmantle, Conqueror's Flail, Teferi's Protection, Indomitable Archangel, Leonin Abunas Disruption: Dispatch, Aura Shards, Scavenging Ooze, Swords to Plowshares, Dromoka's Command, Beast Within, Return to Dust, Wrath of God, Day of Judgment, Phyrexian Reclamation, Fumigate, Austere Command, Rest in Peace, Relic of Progenitus, Nature's Claim, Sylvan Reclamation Recursion: Sword of Light and Shadow, Nahiri, the Lithomancer, Buried Ruin