I have about 15-20 really good exercises. I say 'really good' because they have certainly helped me to do a few nifty things. I have also been practicing them on and off since I was a teenager. Probably started using exercise balls at 18 - started squeezing a handball at 13 (at the behest of my late uncle Tony who had forearms like popeye) 100 times a night - I even popped a few in my day - provided that they were new handballs. The older they get the harder they are to pop.
For intense finger training, try a black paddleball. Only with our finger-tips. When you can start to depress the ball you know you are getting somewhere.
Try pinch gripping a 45 lbs. weight plate from the gym - and seeing how long you can hold it. I periodically do 5 minutes per hand - but I just drop them at the 5 min mark. I don't have all day to hold them. I've done them for up to 10 minutes.
Also, try hanging by your fingers from a chin up bar. See how long you can do it.
Two finger push ups. Before I could do them on the floor, I used to do them against the wall and get my angle lower and lower.
Here are just a few ideas - try 'em out and let me know.
I'm glad people are interested in all that finger stuff/grip strength - I'll definitely be putting something on video soon.
Peace.