Since you brought it up on the "CAFE JOHN in Jomtien Complex" topic, I think we ought to have a separate topic for people looking for vegetarian choices.
I'm guessing you are probably well aware that a Google search for "vegetarian restaurants in pattaya" brings up many.
Turkish and Indian restaurants usually have vegetable-only options and, of course, virtually every Thai restaurant has vegetable-only options.
If you are in Pattaya in mid September to early October, usually at some point during that time period there is an annual week-long vegetarian festival, where all kinds of vegetarian foods can easily be found all over town. Especially along Beach Road all kinds of stalls are set up and there are even places giving away vegetarian dishes for free.