Shield of Winds: Protects from trip and assassin kicks. (This is a good one to keep up when just walking around.)

Shield of Waves: Protects against cranial, lets you breath underwater.

Shield of Ice: Protects against pincer.

Shield of Flames: Seems to protect against blackjack, supposedly assassinate, burns people who get too close.

Shield of Electricity: Reacts violently (sometimes) when people hit you with metal weapons.

Shield of Earth: Protects against bearcharge.

Shield of Slime: Supposedly protects against lash (never really used it.)

There are almost certainly things that they do that I'm completely unaware of, too.

The minor shields do things, too. Like earthshield stops dirt kicking and airshield stops assassin smoke/dust, which is super helpful.

When it comes to flight, you're gonna want to have a bunch of flight potions with you. I would walk around with Shield of Winds up, so no one could trip me, but if you're gonna fight someone who's not an assassin you're probably gonna want to use a different greater shield and quaff a flight potion before you fight.