All of the standards for gloves, but it is basically impossible to find one that fits me.

My hand is about the size of a Mac keyboard. As in I lay it put flat and stretched I have my thumb on the fn to the left, my little finger on the right arrow to the right, the base of my hand at the bottom of the touchpad, and my index finger on the f8 key. I think the last pair I successfully bought was XXXL...and was still a bit small.

Yep those are some big hands! It would be almost impossible to to get custom made, standards compliant gloves too I imagine.

Do you have any recommendations for gloves that dampen vibrations for bikers and are comfortable? Would something like Olympia motorcycle gloves with gel in them be a good choice?

You mention you have a lot of gloves - what are they all used for if you don't mind me asking?

I would look at changing the grips first, coupled with gloves that have a seamless palm area, like the Fox Ranger or Dirt Paw gloves. You can get softer grips than this but I personally use SRAM's locking foam grips. The soak up vibration but the uniformity gives them a predictable rigidity when handling the bike.

I have gloves for: Working on cars; Cold hiking, even colder hiking; summer mountain biking, winter mountain biking, armored downhill MTB gloves; summer commute cycling, winter commute cycling; weight lifting, and miscellaneous woolen gloves for when my hands are cold and I'm doing nothing else.