Mostly posting this so I can reference it.
The first thing that I thought about when
Rayami, First of the Fallen was printed focused on one primary interaction: sacrificing creatures as a cost in order to add blood-countered abilities via direct replacement effects such that the entire purpose of the sacrifice is the cost itself. As this type of gameplay action is entirely unreactable, so long as a relevant ability is in play and your opponents suspect/see a sacrifice outlet you can act as though Rayami already has the ability. Barring some other purpose,
Path to Exile on Rayami with
Gladecover Scout is nearly the same as if it were already exiled with a blood counter. I additionally focused on having a low curve of creatures and due to my reliance on the sacrifice effects, I have a lot of redundant abilities.
The downside to Rayami is closing out games quickly, because there are literally no creatures in these colors with doublestrike. I find +1/+1 counters to be the most resilient because the counters are not on a second card, and are just as difficult to disrupt.
Mana dorks with abilities
Creatures with more than blood abilties
Other sources of increased power
Destroy the Board, reap the Reward
1 Rayami, First of the Fallen
1 Gladecover Scout
1 Slippery Bogle
1 Invisible Stalker
1 Silhana Ledgewalker
1 Bassara Tower Archer
1 Nightveil Predator
1 Rhonas the Indomitable
1 Kefnet the Mindful
1 Bontu the Glorified
1 Stonecoil Serpent
1 Coast Watcher
1 Scryb Ranger
1 Great Sable Stag
1 Phyrexian Crusader
1 Vampire of the Dire Moon
1 Banehound
1 Uktabi Drake
1 Vault Skirge
1 Gurmag Swiftwing
1 Bay Falcon
1 Zephyr Falcon
1 Hovermyr
1 Mirri, Cat Warrior
1 Dimir Spybug
1 Drakewing Krasis
1 Birds of Paradise
1 Beastcaller Savant
1 Sylvan Caryatid
1 Leyline Prowler
1 Indulgent Aristocrat
1 Sanguine Spy
1 Yawgmoth, Thran Physician
1 Eradicator Valkyrie
1 Drana, Liberator of Malakir
1 Roalesk, Apex Hybrid
1 Necropolis Regent
1 Questing Beast
1 Baleful Strix
1 Hydroid Krasis
1 Cerulean Drake
1 Evolutionary Escalation
1 Blackblade Reforged
1 Conqueror's Flail
1 Village Rites
1 Skulltap
1 Deadly Dispute
1 Altar's Reap
1 Costly Plunder
1 Plumb the Forbidden
1 A Little Chat
1 Bankrupt in Blood
1 Diabolic Intent
1 Neoform
1 Eldritch Evolution
1 Prime Speaker Vannifar
1 Culling the Weak
1 Mutual Destruction
1 Spark Harvest
1 Bone Shards
1 Eaten Alive
1 Bone Splinters
1 Make Disappear
1 Culling Ritual
1 Pernicious Deed
1 High Market
1 Rogue's Passage
1 Command Tower
1 Exotic Orchard
1 Waterlogged Grove
1 Dreamroot Cascade
1 Yavimaya Coast
1 Shipwreck Marsh
1 Darkslick Shores
1 Deathcap Glade
1 Llanowar Wastes
1 Woodland Cemetery
7 Island
9 Swamp
8 Forest
//Sideboard