37 cards where the text includes “flash” and it’s legal in Commander and the text includes “though they had flash”

Alchemist's Refuge (The Lost Caverns of Ixalan Commander #318)
Aluren (Tempest Remastered #165)
Arlinn, the Pack's Hope // Arlinn, the Moon's Fury (Innistrad: Midnight Hunt #211)
Arlinn, the Pack's Hope // Arlinn, the Moon's Fury (Innistrad: Midnight Hunt #211)
Borne Upon a Wind (The Lord of the Rings: Tales of Middle-earth #44)
Breath of the Sleepless (Crimson Vow Commander #11)
Cherished Hatchling (Rivals of Ixalan #124)
Complete the Circuit (March of the Machine #52)
Emergence Zone (War of the Spark #245)
Final-Word Phantom (Murders at Karlov Manor Commander #22)
Gandalf, Friend of the Shire (The Lord of the Rings: Tales of Middle-earth #50)
Gandalf the White (The Lord of the Rings: Tales of Middle-earth #19)
Heliod, the Radiant Dawn // Heliod, the Warped Eclipse (March of the Machine #17)
Heliod, the Radiant Dawn // Heliod, the Warped Eclipse (March of the Machine #17)
High Fae Trickster (Foundations #40)
Hypersonic Dragon (Ravnica: Clue Edition #196)
Kianne, Corrupted Memory (Duskmourn: House of Horror Commander #2)
Leyline of Anticipation (Commander Legends: Battle for Baldur's Gate #726)
Liberator, Urza's Battlethopter (The Brothers' War #237)
Najal, the Storm Runner (Dominaria United #208)
Quick Sliver (Commander Masters #907)
Raff Capashen, Ship's Mage (Commander Masters #351)
Rattlechains (Crimson Vow Commander #110)
Renari, Merchant of Marvels (Commander Legends: Battle for Baldur's Gate #90)
Rootwater Shaman (Tempest #84)
Sally Sparrow (Doctor Who #155)
Shimmer Myr (Commander Masters #409)
Sigarda's Aid (Commander Legends #384)
Singer of Swift Rivers (The Lost Caverns of Ixalan Commander #98)
Skittering Cicada (Commander Masters #717)
Teferi, Time Raveler (Ravnica Remastered #232)
Tidal Barracuda (Commander 2020 #39)
Valley Floodcaller (Bloomburrow #79)
Vedalken Orrery (Double Masters 2022 #317)
Vernal Equinox (Mercadian Masques #283)
Vivien, Champion of the Wilds (Commander Legends: Battle for Baldur's Gate #838)
Winding Canyons (Weatherlight #167)
Wizards of Thay (Commander Legends: Battle for Baldur's Gate #105)
Yeva, Nature's Herald (Ravnica Remastered #162)

This search is finished. Now the real work can begin.