After Russia invaded the country, Ukraine's post office (Ukrposhta) decided to hold a contest to design a stamp that illustrated "Ukrainians' determination to defend their land". Out of 500 submissions, Ukrposhta chose 20 designs as the finalists.
(Paweł Jońca's illustration would also have made an amazing stamp.) Many of the finalists, including the winning entry (middle stamp above), reference the Ukrainian soldiers on Snake Island who told a Russian warship "Go fuck yourself". Ukrposhta is now working on getting the winning stamp printed so that people can use it for postage — because, perhaps unbelievably, the post office continues to deliver the mail & packages throughout much of the country. (thx, @jackisnotabird)