TMR stands for tunnelling magnetoresistance, and it is the newest way to read thumbstick position without physical contact. Like Hall effect it cannot wear out, so it does not develop stick drift, but it resolves smaller movements and draws less power doing it.

Lower power draw is the practical difference. On a wireless controller the sticks are sampled constantly, so a more efficient sensor shows up directly in battery life between charges.

TMR boards sit at the top of the controller range and are usually paired with the other premium parts - magnetic or optical triggers, higher polling rates and remappable back buttons.