How about a calisthenics workout poster that he can hang up in his workout space? There are many options online that provide instructions and illustrations of different exercises. You could also consider getting him a calisthenics book that he can read and use as a reference for his workouts. Alternatively, you could get him a set of resistance bands or a pull-up bar to help him with his exercises. Another idea could be a personalized water bottle or workout bag with his name or initials on it, so he can stay hydrated and carry his gear around in style.
Or you can get him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.