Inspired by this question: Which languages was Gandalf proficient in?
Gandalf says the following:
"I once knew every spell in all the tongues of Elves or Men or Orcs, that was ever used for such a purpose."
Do we ever see orcs use spells?
Leaving aside how you interpret Gandalf's words, off-hand I can think of at most two examples of Orcs using magic, though neither are without caveats:
The Goblins of the Misty Mountains
[Bilbo] could not go to sleep for a long while; and when he did sleep, he had very nasty dreams. He dreamed that a crack in the wall at the back of the cave got bigger and bigger, and opened wider and wider, and he was very afraid but could not call out or do anything but lie and look. Then he dreamed that the floor of the cave was giving way, and he was slipping-beginning to fall down, down, goodness knows where to.
At that he woke up with a horrible start, and found that part of his dream was true. A crack had opened at the back of the cave, and was already a wide passage.
The Hobbit Chapter 3: "Over Hill and Under Hill
Is this magic? I don't know; it certainly seems magical.
Grond (emphasis mine)
The drums rolled louder. Fires leaped up. Great engines crawled across the field; and in the midst was a huge ram, great as a forest-tree a hundred feet in length, swinging on mighty chains. Long had it been forging in the dark smithies of Mordor, and its hideous head, founded of black steel, was shaped in the likeness of a ravening wolf; on it spells of ruin lay. Grond they named it, in memory of the Hammer of the Underworld of old.
Return of the King Book V Chapter 4: "The Siege of Gondor"
The sticking point here is that we don't know who lay those spells; it may have been the Orcs, or it may have been one of the Nine, or even Sauron himself.
However, in neither case do we actually see these spells being cast; we never see an Orc in the process of casting a spell.
Gandalf didn't say it was the orcs who use spells. He said spells (used by anyone) in the tongues of Elves or Men or Orcs (that is, those species use those languages for everyday use, not spells).
Some higher orcs speak the Black Speech.
We know one person who used a spell in the black speech: Sauron. He's used the spell to forge the One Ring.
I'm more surprised that there'd be anyone who used spells in the tongues of Men. I imagined most Men would use elvish languages for spells.