59 cards where (the card types include “ooze” or the text includes “changeling”) and the color identity ≤ GU

Acidic Slime (Commander Masters #270)
Aeve, Progenitor Ooze (Modern Horizons 2 #148)
Amoeboid Changeling (Lorwyn #51)
Ancient Ooze (Scourge #112)
A-Ochre Jelly (Adventures in the Forgotten Realms #A-196)
A-Oran-Rief Ooze (Zendikar Rising #A-198)
Biogenic Ooze (Ravnica Allegiance #122)
Bioplasm (Guildpact #81)
Biowaste Blob (Commander Legends #219)
Birthing Boughs (Modern Horizons #221)
Bloodline Pretender (March of the Machine Commander #350)
Chameleon Colossus (Forgotten Realms Commander #153)
Changeling Titan (Lorwyn #200)
Consuming Blob (Innistrad: Midnight Hunt #177)
Corrosive Ooze (Dominaria #158)
Ego Erasure (Lorwyn #59)
Experiment Kraj (Commander Masters #337)
Experiment One (Ravnica Remastered #137)
Faceless Agent (Jumpstart: Historic Horizons #1)
Game-Trail Changeling (Morningtide #123)
Gladewalker Ritualist (Kaldheim #392)
Gluttonous Slime (Planechase Anthology #65)
Gobbling Ooze (Return to Ravnica #126)
Green Slime (Commander Legends: Battle for Baldur's Gate #680)
Guardian Gladewalker (Kaldheim #174)
Inexorable Blob (Shadows over Innistrad #212)
Invasion of Muraganda // Primordial Plasm (March of the Machine #192)
Invasion of Muraganda // Primordial Plasm (March of the Machine #192)
It Came from Planet Glurg (Unfinity #169)
Littjara Glade-Warden (Kaldheim #182)
Littjara Kinseekers (Kaldheim #66)
Manaplasm (Conspiracy: Take the Crown #186)
Masked Vandal (Kaldheim #184)
Maskwood Nexus (Commander Legends: Battle for Baldur's Gate #865)
Mistwalker (Kaldheim #68)
Mitotic Slime (New Capenna Commander #302)
Moritte of the Frost (Kaldheim #223)
Mothdust Changeling (Modern Masters #53)
Mwonvuli Ooze (Weatherlight #135)
Ochre Jelly (Adventures in the Forgotten Realms #196)
Oran-Rief Ooze (Zendikar Rising #198)
Orvar, the All-Form (Kaldheim #70)
Predator Ooze (Commander 2020 #185)
Prime Speaker Vannifar (Ravnica Allegiance #195)
Printlifter Ooze (Murders at Karlov Manor Commander #40)
Ravenous Slime (Commander 2018 #34)
Realmwalker (The Lost Caverns of Ixalan Commander #250)
Scavenging Ooze (New Capenna Commander #309)
Shapesharer (Lorwyn #85)
Slogurk, the Overslime (Innistrad: Midnight Hunt #242)
Slurrk, All-Ingesting (March of the Machine Commander #312)
S.N.O.T. (Unhinged #111)
Splitting Slime (Conspiracy: Take the Crown #72)
The Bears of Littjara (Kaldheim #205)
Turtleshell Changeling (Lorwyn #94)
Universal Automaton (Modern Horizons #235)
Vannifar, Evolved Enigma (Murders at Karlov Manor #241)
Webweaver Changeling (Double Masters 2022 #164)
Wings of Velis Vel (Modern Masters 2015 #70)
Woodland Changeling (Lorwyn #242)

The orcs’ banner sends a clear message: “You've reached the end of this search.”