If you count basic calculus as high school level, TI89's can do symbolic integration. They're usually banned on tests for that exact reason tho.

The TI-89's have the same shell as the TI-83. I took the shell off the 83 and put it on the 89 as well as replacing some of the buttons.

I used this on tests that banned the TI-89.

Can it do anything non-trivial? The algorithms for symbolic integration are extensive.

My Casio could do numeric differentiation and integration. I used this to double check my answers in my exams.

In fact, it still can as I still own and use it to this day.

It's quite good for what it is. Of course it will lose to Mathematica but I used mine heavily throughout physics to derive things symbolically.