The longest series of Christmas Seals which honor a different holiday, began in 1987. Spring ALA seals have Easter themes, and a whole book could be written about them.
Several other holidays were featured on American Lung Association Christmas Seals that collectors may not be aware of. Chanukah seals were issued from 1997 thru 2003, and the ALA of SE Florida issued Kwanzaa seals in 2001 and 2002 which feature Curtis, the comic strip of cartoonist Ray Billingsley. The 2001 had a finer roulette at the fold than the 2002 issue. Finally, in 2003 The ALA celebrated Halloween and Thanksgiving, along with Christmas Seals, all on the same sheet.
Collectors have observed a rise and fall of the number of Christmas Seal varieties, but as the landscape of America changes other holidays could be considered by the ALA. How about Cinco de Mayo, Diwali, or Ramadan?
I almost forgot, The first year US Christmas Seal, 1907 type 2, also honored "New Year" .