Thanks to the large vegetarian Buddhist population in Taiwan, vegan buffets are very common in Taipei. I think the first one we ate at was at a food court in a mall and it had the word vegetarian in English. Once you’ve been to one or two you start to recognize the look of them. Some are bigger and better than others, but they all have a pretty similar set up. 
Here’s how they work.
You will see one main long counter filled with various plates of food. And as you enter the place you pick up either a paper plate or to-go box along with a set of tongs. Then you peruse the selection of foods set up on the buffet. Take whatever and however much you want. Don’t be surprised if there are a lot of things that look like meat – it’s amazing all the things they can do with tofu here! Although that said, if there’s fish staring you in the eyes or bones sticking out of the meat, then it is meat and you are NOT at a vegetarian buffet… you’re just at a regular Taiwan buffet style restaurant! 😉
Once you’ve loaded your plate with everything you want bring your plate to the counter and set it on the scale. You pay according to the weight of your food. For me typically a meal is about $150NT. The clerk will also probably ask you if you want to pay for a bowl of rice (between 10 -30NT).
After you pay, grab a pair of chopstick and find a place to sit. You’ll also probably see one or two large vats of soup in a corner somewhere, that’s free to enjoy with the meal. (One may be sweet and the other savory) Our understanding is that this is in response to the fact that tap water isn’t safe to drink. So instead of supplying free tap water, you get a free thin soup that serves as your beverage.
The Food
In my experience the cooked veggies are always cold. This takes some getting used to, but it’s grown on me. And as I said, there’s also usually a lot of fake meat. Some of it I really like, some of it not so much.That’s part of the learning curve with veggie buffets. The first time I went to one I was so excited at the sight of all these piles of food I knew for sure was safe to eat. But then trying the dishes dampened my enthusiasm. There were a few dishes I liked and wished I’d taken more than a dab of, others were meh and still others went in the never-again category (bitter-melon, I’m looking at you). But the more you go to vegetarian buffets the more know what you like and dislike. So each time its a better and better experience.
Our favorite Vegetarian buffet is this one off Dazhi station on the Brown Line.