Its also important to remember the difference between card color and color identity
This presents a whole new problem in the entire pacing of your deck if theres any impedance at all
It doesnt always perform, but being able to draw a card off of any non-mana activated ability on a creature or land has a lot of potential

Commander (1) 1 Valgavoth, Harrower of Souls Creatures (32) 1 Barbflare Gremlin 1 Blood Artist 1 Blood Seeker 1 Braids, Arisen Nightmare 1 Brash Taunter 1 Falkenrath Noble 1 Fate Unraveler 1 Florian, Voldaren Scion 1 Gleeful Arsonist 1 Gray Merchant of Asphodel 1 Harsh Mentor 1 Kederekt Parasite 1 Mogis, God of Slaughter 1 Morbid Opportunist 1 Nightshade Harvester 1 Persistent Constrictor 1 Rampaging Ferocidon 1 Solemn Simulacrum 1 Stormfist Crusader 1 Vial Smasher the Fierce Artifacts (11) 1 Arcane Signet 1 Basilisk Collar 1 Fellwar Stone 1 Lightning Greaves 1 Mind Stone 1 Rakdos Signet 1 Sol Ring 1 Sance Board 1 Talisman of Indulgence 1 Thought Vessel Enchantments (5) 1 Bastion of Remembrance 1 Enchanter's Bane 1 Spiked Corridor // Torture Pit Instants (6) 1 Blood Pact 1 Chaos Warp 1 Infernal Grasp 1 Rakdos Charm 1 Suspended Sentence Sorceries (7) 1 Blasphemous Act 1 Feed the Swarm 1 Grab the Prize 1 Light Up the Stage 1 Sadistic Shell Game 1 Sign in Blood Lands (24) 1 Temple of the False God

This applies whether they go the graveyard, are returned to hand, exiled or removed in any other way
However, there's not much else giving the card value right now - maybe history will tell a different story