Also double-sided. AFAIK there weren't any single-sided LDs, which meant the unused side had to be filled with something else, like this memorable graphic: https://www.youtube.com/watch?v=QwTDdyZTX48
The dead side of A Video Standard [0] was white opaque plastic. Still a physical side, but not a readable one obviously. Closest I’ve seen to a single-sided disc.
Aside from very early prototypes, there were LD singles which were thinner and made more like CD's. Mostly 8" but there were a few 12"s made by Sonopress in Europe.
