Kodee, I just saw your Play Dead post. I didn't realize you were looking for simple little tricks for therapy work. (I was thinking more complex tasks to keep your dog's brain working with my above suggestions).
Here's a couple.
Downward Dog (my therapy dog instructor called this the Gracious Bow). When your dog stretches, as he stretches backward (the "downward dog" movement in yoga), label and reward that, and mark it with a hand signal.
My beagle mix does this as Downward dog, just for fun. My therapy dog instructor tells her dog to Say Hello, and she (the instructor) leans forward and makes a gracious handsweep (as though she were greeting royalty). The dog then does the backward stretch which looks like a bow. The instructor says she likes this as an option for shaking hands for big dogs because sometimes, our big kids are kind of clumsy shaking hands.
Or, you can take yawns and just make them tricks themselves. I've been trying to do this with Camper because he won't just stretch backward (he's a forward and backward stretcher, every time). So when he stretches in the morning, or after naps, I make an exaggerated "oh! Yawn!" and stretch myself. In time, (he's not picking this one up very quickly. Probably because he's groggy when he's yawning.), I expect I can get him to stretch and yawn on command. Kids love this sort of stuff. "Oh, it's bedtime. Camper is tired." Yawn, Stretch.
Zamboni also Boogies on command. When she would get wet, after the bath or whatever, and shook, we labeled that behavior and treated and hoorayed for it (we originally called it Shake, and wouldn't you know it, she stopped shaking off to offer her paw. Duh. Shake means Here's My Paw. So shaking off is Boogie). This is also helpful when your dog is wet and muddy, and you want them to shake off before they get into the car.
When he was a puppy, I trained Camper the Commando move, crawling forward on his tummy, just by putting snacks in front of his nose then edging them out a bit so he'd have to reach to get them. He learned it, but as he got older, it just didn't work well with his hip structure or something. He kept popping his rear end up. (So I ended up dropping that from his repertoire.) I know someone that does the same trick, but her command, instead of simply "commando" is "Water! Water in the Desert!" And her dog crawls along the ground. It's hysterical to watch.
One of my trainers has a dog that knows all sorts of tricks. One of them is the dog salutes. She says "hello Sir," and salutes him. He salutes back. She said she just put a piece of tape very lightly on his eyebrow, then when he went to push it away, she said the command words, Hello Sir, and the hand signal, the salute...and lots of snacks of course.
Her dog also sneezes on command. When your dog sneezes, mark it "achoo!" (or Gazuntight or Bless You!) (wipe your nose for the hand signal) and treat. A friends dog does a similar trick where the friend says "achoo!" and the dog pulls a Kleenex out of the box and brings it to her. Basically, anything your dog does, you can make it a trick. Just watch him throughout the day and think, would THAT be cute if done on command? Then mark it with a word, a cute hand signal, and give lots and lots of treats.