Like you can buy wood laminate instead of a proper boarded floor.
Can you get tiles that look like exposed bricks to stick on
plasterboard, that look convincing?

Yes. The best ones are actually just slivers of brick. You apply using a
suitable bonding pattern. Some sort of modified Flemish bond, with
variations to break up the pattern looks far better than a stretcher bond,
which looks cheap, miserly and modern. You finish off by pointing the tiles
with mortar, just like a real wall. The effect is indistinguishable from a
real brick wall if done well.

Christian.