MTGNexus

Not much to see here... just a budget Volrath, the Shapestealer counters shenanigans deck. Comes in at time of writing at a hair over $110, but you can drop this to ~$90 by substituting out The Great Henge. Some key things to copy with Volrath:

• Cephalid Constable -- Really wreck the defending player's day.
• Cold-Eyed Selkie -- Draw 7? Yessir.
• Elusive Tormentor -- Unblockable and nigh-indestructible once transformed into Insidious Mist.
• Jodah's Avenger -- All the keywords.
• Mist-Syndicate Naga -- The copies will be 7/5s that can copy other creatures themselves. Spicy!
• Needle Specter -- A poor man's Nicol Bolas.
• Thought Sponge -- Flash it in on not your turn to guarantee a counter, then copy it before Volrath dies to draw 7.

Sweet list. Given how spicy Volrath is with Mist-Syndicate Naga, I am surprised not to see Spawnwrithe in your deck as it has a similar effect but is a much better Volrath target (since it survives a -1/-1 counter being placed on it AND it has trample). Giant Adephage is a similar effect, but is less useful due to the massive CMC.

I've mostly abandoned this list in paper since the pandemic squashed my playgroup, but wanted to do a quick review of recent sets to see what could fit the theme.

Ikoria:

• Mutate in general. Key includes: Gemrazer, Glowstone Recluse, Sea-Dasher Octopus, Auspicious Starrix.
• Zagoth Triome
• Emergent Ultimatum
• Mythos of Brokkos
• Chevill, Bane of Monsters
• Back for More

Zendikar Rising:

• Bala Ged Recovery // Bala Ged Sanctuary
• Inscription of Abundance
• Scale the Heights
• Oran-Rief Ooze
• Skyclave Shadowcat