This thread has a huge number of effects that can be used, so you may find it worth mining for inspiration. I probably ought to add some effects to it to bump it up again.
The Augustan Brotherhood (Virgilian magi) from Rival Magic love being court wizards, and want to pursue political ends to enact their vision. By creating big animated creations as mobile siege engines (obscenely expensive on vis, but very cinematic) or by creating structure size rites to destroy stone buildings or spoil all the food in a building, they can be masters of siege warfare.
All types of hedge magi could annoy a covenant by trying to locate and steal their vis, as a bid to deny the covenant their resources and boost the hedge mage's own power.