The LEGO Gar Saxon minifigure was first introduced in the 75316 Mandalorian Starfighter set in 2021. You can look for this set at your local LEGO store, online marketplaces, or other LEGO retailers. With a bit of luck, you can still get the set here, despite the EOL in December 2022. Alternatively, you can search for the individual minifigure on websites like BrickLink and Rebrickable.