Just a few things I've had success with over the years and looking back to my personal training days.
Weights of course but legs give the most value to boost T. Squats, deadlifts, lunges, Bulgarian split squats, etc. At one point I'd pair legs with upper body almost every day, but do a different leg exercise each time. Leg exercises 4X per week is much better than leg day once a week.
Stretching and using a foam roller. Highly underrated. When tight blood flow is heavily restricted in the glute, pelvic and lower back region.
Jogging in the sun. Run if you like. But moderate jogs in the sun are great. Hiking too. Great vit D and jogging really helps your heart and blood flow. There has always been something about getting a good sweat and doing moderate cardio in the sun which had my libido shoot thru the roof the next day.
L-Arginine- blood flow. Zinc/Mag as others have mentioned.
Berries mixed with my smoothie/protein shakes. I'd included powder maca root.
Red meat every day.
Pistachios for snacking.
No porn whatsoever. That is a big one. That stuff will drain even the best of men of their vitality.
I started taking Ubiquinol. Co-Q10 is great for the heart/brain, blood circulation, mood stability.
I think testosterone is highly correlated with a healthy lifestyle. Have a decent amount of muscle, stay fit, move/exercise, get sun, eat meat, eat fruit, and stretch and improve blood circulation. Blood circulation is underrated. Chronically. It ties directly to the health and well being of your entire body, helps you feel younger and fresher, improves your mood and mental state. And I do think all of that ties into testosterone, libido and vitality.