If you could lube up the water pump pulley, I think that would be your best place to try and leverage the belt off, but you would have to get something under the belt to do it, and then clean up the mess afterwards. I think it'* a pretty tight area, so it may be slightly hazardous.
As mentioned, you could cut the belt, just make sure you are clear of the tensioner when you snip it. The movement should be fairly minimal when tension is released, probably about 2-3 inches.
You can also heat something really hot and burn through the belt too, and tension would release just as before, only you could be further away from it.
I don't think removing any accesories is a good idea at all, because then you would have an accessory being flung down, assuming it even was enough to get it off.
The only other way is to possibly stick something between a belt and a pulley and turn the engine over, but you would be careful that you don't hit the end of travel on the tensioner, and you still will want to be careful releasing the tension, because you don't want it to go straight to your finger that was somewhere it shouldn't have been.