Everyone has a tradition for anything and everything they do. People are superstitious and this continues for astronauts. Every country and company that has launched a rocket has their own space launch traditions.
Russia has a few space traditions, 14 to be exact, all of which can be found here. Some of them are expected such as raising the country’s flag, putting a rose of Yuri Gagarin, and being blessed by an Orthodox Christian Priest.
Not to be left out of the mix, NASA does have its own space traditions such as the Smithsonian magazine notes that playing poker until the commander plays the worst possible hand and eating a meal of steak, eggs and cake are 2 traditions. During the Space Shuttle launches, a tradition for the engineers was the lunch of beans and cornbread for a successful launch. 
But what about the space launch traditions for the new space launch companies such as SpaceX? How future companies such as Boeing and others continue or forge their own traditions? It looks like planting trees, and slapping stickers on stickers are what have been discussed. NASA administrators have said they do have the responsibility to create new traditions, but what they take from the Russians in terms of traditions and forge on their own will be seen.
In regards to traditions for countries that can be expected to shortly have manned flight such as India will do is unknown. Plus, finding information about what the Chinese do about their traditions is hard. It begs the question of what future generations will do for good luck and traditions?
Sources And Further Reading
 = https://www.smithsonianmag.com/smart-news/astronauts-pre-launch-traditions-180956151/
 = https://www.nasa.gov/content/beans-a-launch-tradition/