Racing car tiles.
These are the first household tiles to appear on the site, and could well be the last! They turned up at a car boot sale, and they depict various single-seater Formula 1 racing cars. Each measures approx 11cm x 11cm. My guess is that they date to the early 1960s, as they feature both front- and rear-engined Grand Prix racing cars. As well as on the bathroom / bedroom tiles shown below, I've seen some of these images reproduced on bedroom door name plaques (I had one as a child), and also on porcelain tankards, so they're probably still quite commonly found.