I think the abilities of the Keyblade actually vary on three factors:
1. The origin of the Keyblade (this could play a major role in it's appearance and attributes)
2. the Keychain attached to the blade (this would further distinguish it's appearance)
3. The skill of the one weilding the blade. (this must always be accounted for as one Keyblade wielder may not have the skills necessary to wield certain Keyblades.)
That being said, I don't think there is a way to accurately determine all the abilities of a keyblade. There might be some keyblades whose ability is to control other Keyblade wielders, or possibly one with the power to absorb another's Keyblades into yours. There could be one for shapeshifting, or one for invisibility. Heck, there could be one that was specifically designed for fighting Heartless, while another is designed specifically for defeating nobodies.
The possibilities are endless!