On November 13th, The Royal Mail will be releasing a special set of collectable stamps celebrating both 50 years of Star Trek as well as the British actors that have had a prominent role in the franchises long history.
Some people have questioned the lack of British actors from Star Trek: Picard such as Harry Treadway and Santiago Cabrera (who though born in Chile, grew up and trained in England). I imagine the lack of them is due to licensing and production issues. Work on these stamps probably began some time last year before Picard aired and I imagine getting the licensing rights and artwork approved may be the reason for this.
Many different options are available and can be seen here at The Royal Mail Shop Website. Also check out their other collections such as Doctor Who, Game of Thrones and more!