NFL alternate helmets: Tracking NFL teams' secondary lids for the 2022 season
Philadelphia Eagles - Wikipedia
The 49ers announce they will wear their alternate black jerseys for home games vs. Vikings (Sept. 14) and Cardinals (Nov. 29) this season. : r/nfl
49ers Unveil Alternate Throwback Uniforms at Annual State of the Franchise Event
14 NFL teams are getting new uniforms and helmets for the 2022 season
LOOK: Colts unveil new black helmet as part of alternate uniform that will be worn for one game in 2023 : r/nfl
Sources: Carolina Panthers To Unveil New Uniforms Prior To NFL Draft : r/nfl
In Review: 2015 Football Uniforms, by Sooner Tracker
The Day After: Nike/NFL FAQ
Why does the visiting team in the NFL generally wear white uniforms? - Quora
Do NFL teams wear new uniforms every game? - Quora
49ers unveil new uniforms with an old look
Is Nike's hold on NFL, college football uniforms in peril? -- Uni Watch - ESPN
An NFL Offseason Offers Hope for Teams, but So Might a Rebranded Look - Front Office Sports