I am no seaweed scientist, but here is what we use:
Nori, unseasoned, comes in sheets and gets wrapped around stuff.
Nori, seasoned (salt, oil, smoked, sometimes chili), comes both in sheets and chopped, eat out of hand or crumble/sprinkle on anything imaginable.
Wakame, comes in long darkest green tangles or chopped (I like buying it chopped), gets dropped in brothy soups (or just broth - a fave here), but be warned that it unfurls to a size quite larger than its dried-up bitty original self
Back before Primal, I used to put a strip of kombu in bean soups - they soften better, the kombu dissolves completely
I recommend just going to a small Asian grocery, make friends with the owner, and just start asking questions and reading the ID label and trying stuff out. You will find favorites very quickly. Somewhere on the bag you should be able to find the English words that identify the type - nori, wakame, laver, kombu, etc. If all that fails, just go to a Japanese sushi restaurant and get an order of the seaweed salad - OMG, I could eat a barrel of that stuff! We have an Asian grocery that I discovered makes an awesome seaweed salad as well, so now I can get my fix from their fridge case instead of going out to dinner.
My bestest tip - once you have found a favorite sea vegetable, SAVE THE PACKAGE for your next shopping trip. Makes getting the same thing next time MUCH easier if you can show the shop owner what you originally got.
I have a mantra that I have spouted for years... "If I eat right, I feel right. If I feel right, I exercise right. If I exercise right, I think right. If I think right, I eat right..." Phil-SC