Okonomiyaki is like a big fat pancake with cabbage and seafood or meat. Most places should be able to make it sans meat and seafood. Egg is used in the batter so it's not suitable for vegans. Usually, you cook it yourself on a hot-plate or it is cooked in front of you. For vegetarians, it's basically just cabbage and batter, but depending on the style of the restaurant, you can ask for other ingredients like soba noodles, kimchee, mushrooms, etc. One problem is that apparently some okonomiyaki restaurants use lard on the hotplate so try to find one which doesn't or be so bold as to ask them to use vegetable oil instead. Another problem is that okonomiyaki sauce sometimes contains fish, so you could ask for it without sauce. Also, they sprinkle fish flakes on it, so remember the magic phrase, 'katsuo-bushi nashi!' ("without fish flakes") Okonomiyaki restaurants also have other side dishes like enoki mushrooms cooked in butter. Monja, the Tokyo equivalent of okonomiyaki is similar, but sticky and runny.

Take a look at some recommended Japanese restaurants in Tokyo.

SHABU-SHABU, SUKIYAKI, YAKITORI, TONKATSU, TEPPANYAKI, JAPANESE CURRY, GYUDON, ODEN, etc
It's almost impossible to find suitable food at these kinds of restaurants.

 Take a look at some recommended Japanese restaurants in Tokyo.