22 cards where the set is “sld” and (((the collector number >= 1335 and the collector number <= 1351) or the collector number is “731” or the collector number is “1387” or the collector number is “1388” or the collector number is “1388a” or the collector number is…

Sigarda's Aid (Secret Lair Drop #731)
Gisela, the Broken Blade (Secret Lair Drop #1335)
Bruna, the Fading Light (Secret Lair Drop #1336)
Brisela, Voice of Nightmares (Secret Lair Drop #1336b)
Archangel of Thune (Secret Lair Drop #1337)
Court of Grace (Secret Lair Drop #1338)
Commander's Plate (Secret Lair Drop #1339)
Angel (Secret Lair Drop #1340)
Spirit (Secret Lair Drop #1341)
Angel of Finality (Secret Lair Drop #1342)
Angel of the Ruins (Secret Lair Drop #1343)
Arden Angel (Secret Lair Drop #1344)
Breathkeeper Seraph (Secret Lair Drop #1345)
Dawnbreak Reclaimer (Secret Lair Drop #1346)
Valkyrie Harbinger (Secret Lair Drop #1347)
Plains (Secret Lair Drop #1348)
Plains (Secret Lair Drop #1349)
Plains (Secret Lair Drop #1350)
Plains (Secret Lair Drop #1351)
Gisela, the Broken Blade (Secret Lair Drop #1387)
Bruna, the Fading Light (Secret Lair Drop #1388)
Brisela, Voice of Nightmares (Secret Lair Drop #1388b)

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