>>1
Many of these you wouldn't want to take together and everyone's physiology is a little different so what works on average may not work for you, regardless this may be useful: https://darktka.github.io/focus.png
Non-pharmaceutical methods might include meditation, "implementation-intentions", and avoiding environments with frequent context switching (e.g. videos with shorter scenes, or my involved camera movement, or scrolling a web feed where each item is unrelated to the last, etc.)
