10 cards where it’s legal in Pauper and the text includes “amass” and the text includes “orc”

Deceive the Messenger (The Lord of the Rings: Tales of Middle-earth #47)
Dunland Crebain (The Lord of the Rings: Tales of Middle-earth #82)
Easterling Vanguard (The Lord of the Rings: Tales of Middle-earth #83)
Mordor Muster (The Lord of the Rings: Tales of Middle-earth #96)
Orcish Medicine (The Lord of the Rings: Tales of Middle-earth #104)
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 Torment of Gollum (The Lord of the Rings: Tales of Middle-earth #110)
Treason of Isengard (The Lord of the Rings: Tales of Middle-earth #74)
Warbeast of Gorgoroth (The Lord of the Rings: Tales of Middle-earth #152)

The message was clear to Sorin—time to search for something else.