Germany: Mainzelmännchen (2023)

On matching Cards with Special Postmarks [A third card with the highest value stamp got lost in the mail]:

Germany: Town Musicians of Bremen Special Postmark (2023)

On a matching Card:

[Appendix] Japan: Winnie the Pooh (2023)

Used on a Card with Special Postmark: 

France: Barbie (2023)

Switzerland: Little Prince (2023)

On a matching Card with Special Postmark:

 FDC:

"Faltblatt":

Latvia: World Tales - A Sleep Fairy Tale (2023)

FDC:

France: 75 years Pif le Chien (2023)

"Document philatélique":

Germany: 100 years Disney (2023)

On matching Cards with Special Postmarks [unfortunately the gummed stamps fell off during the mailing process, but the self-adhesive one sticked to the card]:

First Day Sheet:

"Erinnerungsblatt":

New Zealand: Avatar - The Way of Water (2023)

Presentation Pack including among others a FDC:

Croatia: PlayStation Characters (2023)

United Kingdom: X-Men (2023)

Germany: Welfare - Hans in Luck (2023)

On matching Cards with Special Postmarks:

Japan: Peanuts (2023)

Nothing else needed.

On a matching Card with Special Postmark: