This episode is the mail art primer. (re-issue)
Cling vinyl stamps allow the stamps to be used with an acrylic handle for support.
The TAM Rubber Stamp Archive has a collection of prints of rubber stamps mail-artists have used since 1983.
Harriet Tubman stamp for the $20 bill
https://indroneswetrust.tumblr.com/participate
https://www.stampstampede.org/
https://www.jetpens.com/blog/how-to-use-washi-tape/pt/698
https://every-tuesday.com/10-hand-lettering-enhancements/