Flight
Invisibility
Can see buried treasure
make people fall ill or heal heal them
Able to cause plant life to grow or wither
Curses or blessings of luck
Shapeshifting
Ability to summon and control storms
Okay, these are all fairly simple.
Flight: Wings (-1)
Invisibility: this is either an evocation veil or about half of glamors. So either part of evocation or a -1 power.
See Buiried Treasure: Supernatural sense (-1)
Making people ill can fall under evocation or thaumaturgy depending on details. Healing falls under thaumaturgy.
Plants withering can be under evocation, growing is probably best under thaumaturgy.
Luck fits under thaumaturgy and evocations.
Shapeshifting is just the shapeshifting powers.
Controlling storms is big time thaumaturgy. You could model it as a scene aspect, although it seems a little cheap for that to cover a whole area. You'll probably just need to eyeball the cost.
Taming dragons: Well its a dragon. You ride on it. Probably using the drive skill. The actual taming, can be modeled at thaumaturgy. Another option would be to model it as incite emotion (tamed). Or possibly combine the two.
So how I would go about this is
Item of Power
Wings (-1)
Invisibility (-1) (Roll deceit or discipline to be invisible, opposed by alertness or investigation.)
Supernatural Sense (-1)
Evocation/Thaumaturgy (-6)
Shape-shifting (-X)
Incite Emotion (tamed) (-X)
Requires appropriate Aspect: Note this will be compelled a lot to restrict what they can pull off with this build. I.E. "No you may not tame a bear, No you may not try and tame the Merlin. No you don't have the ability to make wards."