What do BETTY BOOP, NANCY DREW, SAM SPADE and MISS MARPLE have in COMMON?

Betty Boop
Betty Boop

What do the iconic fictional characters BETTY BOOP, NANCY DREW, SAM SPADE and MISS MARPLE have in COMMON?

Hint: It has something to do with the year 2026.

Correct answer will be given in a few days (Sunday).

Updates
5 mo
The copyright on each of these characters expired on 1 January 2026, and their works are now in the public domain.
Congratulations to those who knew that.
What do BETTY BOOP, NANCY DREW, SAM SPADE and MISS MARPLE have in COMMON?
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