As an Elemental Shaman with the spells mentioned you will be able dispell as follows:
- Any Curse debuff with Cleanse Spirit
- Any Magic debuff with Glyph of Shamanistic Rage
- Any Disease debuff with Cure Toxins
- Any Poison debuff with Cure Toxins
This leaves only physical effects that cannot be dispelled, which actually cannot be dispelled by anyone.
To expand more generally on this, all player initiated debuffs are dispellable with the exception of physical debuffs and with some limitations I will detail below:
- All dispels are limited to dispelling a subset of the types of debuffs
- Poison - e.g. Deadly Poison - dispellable by Paladin, Druid, Shaman
- Disease - e.g. Frost Fever - dispellable by Paladin, Shaman, Priest
- Magic - e.g. Misery - dispellable by Priest, Warlock, Paladin, Shaman (with Glyph)
- Curse - e.g. Curse of the Elements - dispellable by Mage, Druid, Shaman
- Physical - e.g. Demoralizing Shout - these are not dispellable
- Some debuffs will prevent you from casting any spells which would limit your ability to dispell yourself, e.g. [Hammer of Justice]. However, there are some abilities that allow you to break out of stuns, spells like [Ice Block] and also the PVP trinkets are an example of this.
If you are unsure of what school a debuff falls into you can either mouse over it in game and read the tooltip or look it up on wowhead or wow wiki.
Finally if you do use addons then something like Decursive will actually change your UI in a way that will show you debuffs that you are able to dispell, a lot of unit/raid frame replacements will also provide this same functionality, ElvUI is an example of this.
All of this information was sourced from WowWiki