Moving in with the bad guys. When the Rebels' starfighter had a lot of their toys modify because they were second hands one and I liked to alter them, it's not so much the case with the Imperials, which has only the Tie/D and the TiE/IN with any modifications.

The TIE/PH or Tie phantom is equipped with stealth and cloak abilities, making it a perfect infiltration starfighter.

The TIE fighter was introduced late into the Clone Wars as a prototype which would become the TIE/LN, the classical Tie fighter you see behind.

The TIE/LN (light duty) is a cheaper, weaker, smaller version made for training or to be given to planets who aren't worth giving better starfighters.

The TIE/IN or Tie interceptor was created to match up with the X-wing. It does a good job at that, but is no match in one to one with equal skills pilots. But it is cheaper and easier to produce in mass that his counterpart.

The First Order Tie interceptor is an upgraded version of the previous one, with better everything from hyperdrive to shield to weapons.

The TIE/D is an automated, cheap, sacrifiable drone starfighter used for defense.

The TIE advanced X1 was the first attempt at a real full combat starfighter with shield, hyperdrive, armor and all that. It does a good job at it but is expensive to produce.

The TIE/SK or tie striker is an atmospheric fighter, because, let's be honest, your average TIE fighter has no aerodynamism and can't fly well inside a planet's atmosphere. The Tie striker can do that with ease and is still space-worthy.

The Tie racer is a modified Tie interceptor to become a race starfighter.