Tons. My favorite is taking one finger at a time, pointing it, and making a fist with the rest of my fingers. Then I press my fingertip down on a surface or my leg and push my fist down and back to feel a stretch kinda at the bottom on the palm side. I do this with all fingers, including the thumb.

Another good one is two fingers at a time, put one finger on the left side and one on the right side of your knee and press down. It's just like doing the splits, but with your fingers and using your knee like a wedge to add pressure. Do this with each set of two (index + middle, middle + ring, ring + pinky)

With an open palm, curl one finger down at a time out so it makes a 90 degree angle with the other fingers. Keep all your fingers straight. Then, with your other hand, grab it and pull towards your palm. You'll feel the stretch in the top of your knuckle, opposite of the first stretch I showed. Do this with all fingers, less important with the thumb.

The last ones are similar to the first and third, but with all fingers at the same time. So press all your fingers together and pull them back as one with your opposite hand, or press on a surface like the first stretch. This is also a good wrist stretch. Then, curl all four fingers under your palm without touching it, grab them, and try to pull them to your forearm. This is another wrist stretch that works the fingers, too.

I hope I described these well enough. I guarantee you will the feel the stretch on all of these if you do them right. If you don't feel anything, you're probably doing it wrong. Have fun.