There definitely was a period where there were a LOT of custom pieces, but in more recent sets they seem to be moving away from that. Things are still significa

There definitely was a period where there were a LOT of custom pieces, but in more recent sets they seem to be moving away from that. Things are still significantly more complicated than a set full of 4x2 and 2x2 bricks, but there's very few pieces besides maybe some minifig accessories that are genuinely unique to one or even a few sets.