An @AngelPray noted in the comments, "How many elements are there" depends on which elemental system you're using. It seems like you've already decided on an elemental system, so I'm going to focus on the question posed in the body of your question:
Is there any way I can simplify these?
Let's go through these one at a time:
- Fire: This one's fine.
- Water/Ice: Ice is just frozen water, so you can simplify this one down to just Water.
- Wind/Air: Again, wind is just moving air, so you can simplify this one down to just Air.
- Lightning: I'd change this to Electricity, so it encompasses all forms of electrical energy and not just lightning.
- Earth/Metal: This is a tricky one. Personally, I'd separate these into two separate elements: Earth is (comparatively) soft, and nurturing to life, whereas Metal is cold, hard, and used to construct weapons of war.
- Energy: I think this is too nebulous a concept to be an element in its own right. Energy comes in several different forms - light, heat, electricity - and you've already given most of them their own elements. So I'd remove this one.
- Creation/Life/Plants & Animals: Assuming this is all supposed to be one element, I'd simplify it down to just Life. Plants and animals count as life, after all.
- Destruction/Death: I'd narrow this down to just Death. Like energy, "Destruction" is a nebulous concept that comes in many forms, many of which are already covered by other elements (particularly Fire).
- Time: I'd say this violates your own rule of "no basic universal powers". Besides, if there's an item in your story that that lets people control time, this will open up a million potential headaches for you. Look at Harry Potter and the Time-Turners. I'd just get rid of this one.
- Form: Form of what? Your own form? If the Form Amulet lets you control your own form (i.e. shapeshifting), that's fine. If it lets you control anyone's form, that's kinda overpowered and, like Time, you may need to rethink this one.
- Speed/Sound: Sound could possibly be grouped under Air, as it's really just vibrating air. As for Speed, I'll come back to that one.
- Light: This one's fine.
- Shadow: Can't have light without shadow. This one's fine too.
So the definite ones so far are: Fire, Water, Air, Earth, Metal, Electricity, Life, Death, Light, Darkness. Notice how they form neat, contrasting pairs: water puts out fire, metal conducts electricity, and so on. This is why I haven't included Form, Speed, or Sound: I can't think of anything that any of them would pair neatly with, and so they'd break the pattern.
I'd recommend either sticking with just those ten elements, or adding another pair of opposites for a total of twelve, like the zodiac. I'm afraid I can't offer any suggestion for what that additional pair could be, however. Maybe I'll come back to this answer when I don't have a migraine.