Throughout the world, Köstler (Köstler 
) is an extremely rare unknown gender forename. Much more prevalently, Köstler is the last name as well as the forename.
Max, Hans, Vera, Iris, Otto, Maria, Marco, Michl, Sarah, Silke, Sonja, Alois, Andre, Anton, Anita, Adolf, Cathy, Bernd, Benno, Karin, Katja, Kevin, Nora, Nico, Jens, Jana, Pia, Lea, Tim, Eva, Odo, Uta, Uwe, Marc, Mark, Maxi, Klaus, Sven, Anna, Karl, Kurt, Ralf, Gabi, Leon, Lena, Lina, Lisa, Luca, Alex, and Paula