Manahive

Equivalent cards to “Trazyn the Infinite” (a black artifact creature that combos with artifacts in the graveyard) in black include:

• “Necrotic Ooze” (black) — Copies activated abilities of creatures in graveyards, just like “Trazyn the Infinite.”
• “The Mimeoplasm” (black-green-blue) — Copies creatures in graveyards, but is not mono-black.

Mainly, “Necrotic Ooze” is the best mono-black equivalent. Both use graveyard-activated abilities.