Oh crap I had a big reply written to this but lost it.
Anyway-
Pub fare varies somewhat by time of day, location of a pub, the clientele and what sort of pub it is.
Some pubs serve trendy food.
Tourist pubs will generally serve the fare Americans would be used to in an American Irish pub/restaurant. Traditional Irish foods aren’t usually available as standard in non-tourist pubs, so you’d be hard-pressed to find boxty, colcannon, coddle and the like anywhere but a tourist joint.
A typical light lunch menu might include toasted sandwiches, paninis, normal sandwiches, chicken fillet rolls, ciabatas, soups, salads, chips (or fries
), onion rings, garlic mushrooms and other stuff like that. Some pubs have a selection of vegetarian fare, most don’t specifically.
A typical lunch/dinner in a large pub or one connected to a hotel would probably consist of a carvery with a joint of beef or ham, maybe chicken or turkey, and a fish dish or two. These tend to be served with as much boiled veg (carrots and others) and as much mashed or boiled potatoes as can be piled on the plate. A pasta dish is usually also offered in this set up.
Other pubs will have a set menu with stuff like chicken curry, fish and chips, stew, turkey and ham, chicken and chips, and more sophisticated fare depending again on the pub. No free refills though alas.
I hope this post has been of some use.