There are many choices - it's a blend between French and Indochinese and can be quite varied. It , of course has similarities to Thai, Chinese, but is it's own thing, too.
Seafood and beef are usually two big features as well as pork.
Ban Xeo is really good. Sometimes called a Vietnamese pancake, it's actually a crispy rice-flour crepe with with Nuoc Mam (fish sauce). Nuoc mam is one of the distinctive attributes of Vietnamese food. It's pretty tasty stuff, by itself and even though it starts with fermented fish juice
There are a whole bunch of Pho dishes which is beef with noodle.
Some Vietnamese restaurants have a lot of charcoal-grilled meats and seafood serve over rice vermicelli with Nuoc mam. I eat it with fish.
And yes, they do great fish at some places - whole steamed fish (or fried) with Nuoc mam is wonderful.
They also have both Spring rolls (fried) and Summer rolls which are uncooked and often filled with basil and dipped in peanut sauce (and of course nuoc mam). And if you like your caffeine like me, go for the Vietnamese coffee. It's espresso ground strong spiced coffee with sweetened condensed milk.
I forgot to add, there are often some wonderful huge bowls of soups, too.
I'm glad you are open-minded because it's best to step away from the comfort-zone and discover new things, especially with food!