Your search for "*monster of the abyss*" revealed the following:

Aclazotz, Deepest Betrayal // Temple of the Dead (Showcase)
[The Lost Caverns of Ixalan]

Sold Out

Delver of Secrets // Insectile Aberration
[From the Vault: Transform]

Sold Out

Wheel of Prophecy
[LTGY-EN031 Rare]

Sold Out

Abhorrent Oculus Art Card
[Duskmourn: House of Horror Art Series]

Sold Out

Aboleth Spawn
[Commander Legends: Battle for Baldur's Gate]

Sold Out

Gray Merchant of Asphodel
[Duskmourn: House of Horror Commander]

Sold Out

Cyber Dragon
[BP02-EN039 Mosaic Rare]

Sold Out

Dark Gray
[LOB-EN011 Common]

Sold Out

Manticore of Darkness
[SDOK-EN005 Common]

Sold Out

Abyssal Persecutor
[Commander 2014]

Sold Out

Ash Blossom & Joyous Spring
[SDCB-EN014 Common]

Sold Out

Master of OZ
[SOD-EN035 Ultimate Rare]

Sold Out

Fiend Reflection #2
[LOB-EN021 Common]

Sold Out

Invasion of Ikoria // Zilortha, Apex of Ikoria
[March of the Machine Prerelease Promos]

Sold Out

Blight Titan (Extended Art)
[March of the Machine Commander]

Sold Out

Number 23: Lancelot, Dark Knight of the Underworld
[BOSH-ENSE2 Super Rare]

Sold Out