Omg Alexander Technique, freaking life-changing. I could go on all day about it.
It's kinda like a posture training thing where you slowly move around and meditate on how the muscles in your body are all connected and how the most instinctive human motions are the most optimized.
You aim to enlighten yourself on the natural balance of your skeleton.
Once you get that down, you add in breathwork and an activity such as playing an instrument, dancing, doing sports, or working.
For me it really improves strength, natural ability, balance, precision, reflex, mentality, flexability, and fluidity.
And it just makes you feel happier and more confident cuz your body feels so light and whole when it is sensing its body physics through space.