Romanian Deadlifts without a mixed grip. Reverse EZ Bar curls. Zottman Curls. I think that’s how it’s spelled. Have you tried just looking in the articles or searching “Grip Strength.” If you could do hangs or pull ups with a thick bar or a towel that would work. If your workout space permits the farmers walk even with normal non-fat-grip dumbbells is great for traps and grip.
For variety you should try plate pinching to see how long you can hold a stack of 5 or 10 lb plates together. That’s good for thumb strength.
The Snatch Grip Deadlift without straps is a good grip workout, is different than the stress on your grip that normal dead lifting puts on you, and is pretty much one of the beallendall lifts for anything you want to strengthen.