I read somewhere that paralysis doesn't work on dragons. What about Slow, Damage Health or Lingering Damage Health?

Any other potions I missed?

Resist Fire/Frost

I never remember to drink them when a dragon swoops in though

Restore Health would what I would use against dragons. Only I would use it on me during the battle, not the dragon.

Yeah, I guess I should have said "which offensive potions".

I would suggest using potions that enhance which-ever skill you are using to battle dragons whether archery or a form of destruction. I'm not too fond of up-close dragon fights but I assume that's the only way to actually use a potion on a dragon.

I am sure any of the poisons would work.

Also, you might try the weakness to elemental potions before using that magical attack. Only use the potion that gives them more of what they are already weak to and then use that magic/enchantment. So, give a fire dragon weakness to frost then hit them with a frost blade or spell.

You can apply the poison to the arrow, then shoot the dragon. Just don't miss or you waste the potion and the arrow.

If I use one of those then I often only get one shot and then the dragon is off flying around and too hard to hit. By the time he lands again the potion has worn off.

Unless I am very much mistaken, poison doesn't "wear off". You poison your weapon, and the next time you use the weapon, the poison will be used, no matter how much time passes between the act of poisoning and the weapon usage.

Of course, if you try to hit a flying dragon while your weapon is poisoned with your precious home-brewed specials, then the poison will be wasted (flying dragons are a pain to shoot). Just wait until the dragon enters the hovering pose from which they like to breath at you or until they went to the ground, before you start to waste your arrows.

Damage health/stamina, ravage health/magicka, damage stamina/magicka regeneration. Yes, poisons accumulate. Poisons that have two, or more, effects are best.

If you're using an enchanted melee weapon, it's probable worth poisoning it with a weakness to X potion, where X is the type of enchantment.