56 cards where the text includes “amass” and (the card is available on Paper)

Angrath, Captain of Chaos (War of the Spark #227)
Assault on Osgiliath (The Lord of the Rings: Tales of Middle-earth #285)
Aven Eternal (War of the Spark #42)
Barad-dûr (The Lord of the Rings: Tales of Middle-earth #253)
Bleeding Edge (War of the Spark #78)
Book of Mazarbul (The Lord of the Rings: Tales of Middle-earth #116)
Callous Dismissal (War of the Spark #44)
Commence the Endgame (War of the Spark #45)
Corsairs of Umbar (Tales of Middle-earth Commander #19)
Crush Dissent (War of the Spark #47)
Deceive the Messenger (The Lord of the Rings: Tales of Middle-earth #47)
Dreadhorde Invasion (Commander Masters #866)
Dreadhorde Twins (War of the Spark #126)
Dunland Crebain (The Lord of the Rings: Tales of Middle-earth #82)
Easterling Vanguard (The Lord of the Rings: Tales of Middle-earth #83)
Enter the God-Eternals (War of the Spark #196)
Eternal Skylord (Midnight Hunt Commander #99)
Fall of Cair Andros (The Lord of the Rings: Tales of Middle-earth #124)
Foray of Orcs (The Lord of the Rings: Tales of Middle-earth #128)
Gleaming Overseer (Midnight Hunt Commander #151)
Gothmog, Morgul Lieutenant (The Lord of the Rings: Tales of Middle-earth #87)
Gríma Wormtongue (The Lord of the Rings: Tales of Middle-earth #88)
Grim Initiate (War of the Spark #130)
Grishnákh, Brash Instigator (The Lord of the Rings: Tales of Middle-earth #134)
Herald of the Dreadhorde (War of the Spark #93)
Honor the God-Pharaoh (War of the Spark #132)
Invade the City (War of the Spark #201)
Invading Manticore (War of the Spark #134)
Lazotep Chancellor (Modern Horizons 2 #203)
Lazotep Plating (War of the Spark #59)
Lazotep Reaver (War of the Spark #96)
Lazotep Sliver (Commander Masters #733)
March from the Black Gate (The Lord of the Rings: Tales of Middle-earth #94)
Mindless Conscription (Modern Horizons 3 #101)
Mordor Muster (The Lord of the Rings: Tales of Middle-earth #96)
Moria Scavenger (Tales of Middle-earth Commander #63)
Orcish Bowmasters (The Lord of the Rings: Tales of Middle-earth #103)
Orcish Medicine (The Lord of the Rings: Tales of Middle-earth #104)
Relentless Advance (War of the Spark #64)
Saruman's Trickery (The Lord of the Rings: Tales of Middle-earth #68)
Saruman the White (The Lord of the Rings: Tales of Middle-earth #67)
Saruman, the White Hand (Tales of Middle-earth Commander #8)
Sauron, Lord of the Rings (Tales of Middle-earth Commander #4)
Sauron, the Dark Lord (The Lord of the Rings: Tales of Middle-earth #224)
Shagrat, Loot Bearer (The Lord of the Rings: Tales of Middle-earth #228)
Summons of Saruman (Tales of Middle-earth Commander #70)
Surrounded by Orcs (The Lord of the Rings: Tales of Middle-earth #73)
Swarming of Moria (The Lord of the Rings: Tales of Middle-earth #150)
The Mouth of Sauron (The Lord of the Rings: Tales of Middle-earth #216)
The Torment of Gollum (The Lord of the Rings: Tales of Middle-earth #110)
Toll of the Invasion (War of the Spark #108)
Treason of Isengard (The Lord of the Rings: Tales of Middle-earth #74)
Vizier of the Scorpion (War of the Spark #111)
Warbeast of Gorgoroth (The Lord of the Rings: Tales of Middle-earth #152)
Warg Rider (The Lord of the Rings: Tales of Middle-earth #826)
Widespread Brutality (War of the Spark #226)

Their mind whirled with grand plans, never thinking of what might happen if they got to the end of the list.