I think anything along the lines of kinetic force, light, audio is fair game. Thus:
1. Maneuvers like "soundless steps" or a whole bubble that eliminates sound. Molly's one woman rave is probably also a spirit spell (and it has been used more in a non combat style). You could also try things like hearing someone talk that is too far away to hear or transmit your voice to a location of your choosing.
2. Any kind of veil to the senses, like blocking out sound, blinding someone, making them not smell the poison in their coffee, that kind of stuff. You could create illusions, but as a single target spell, that is probably not that far from breaking the law. Or, if you are operating in a team, take out the light in the room first and then illuminate your enemies for your friends to take out.
3. Well, anything that can be done to one person can be done to a zone. Light up/darken a zone, take away the zones ability to transmit sound or have any sound that enters the zone increased by a whole lot, so that it practically is a sonic weapon.
4. You can block sight, so nobody will even be able to attack you. Sound, so nobody will hear you sneak around. Instead of a standard "Forcefield" spell, you could create a poltergeist "shield": things around you will just jump up, fall off shelves, topple over, etc. to intercept attacks made at you. Especially strong if you have a scene aspect representing some stuff that's lying around (think of a fight inside a library, endless supply or armor-books). Or you could create some holographic duplicates of yourself that run around and distract the enemy for the same purpose.
5. On a kind of silly note: if you have a practitioner that is more along the line of subtle magic, tie their shoelaces. Or limit the friction of their shoes, they won't be able to walk anywhere without hitting the floor every single step (I experienced that first hand a couple weeks ago. No magic, of course, but the whole street was one large sheet of ice.). A Poltergeist-spell comes to mind again, throwing obstacles in the way of everyone moving in a zone.
Hope that helps a bit