B batteries are still made and sold and pack a decent punch for their size, 21.5 mm x 60 mm (.8464 in. by 2.36 in.), producing 1.5 volts and 8350 mAh for the alkaline variety.
I followed your lead - I cut and pasted the text - and this also answered why no 'A' cells either.
It seem there were but like the 'B' size is now largely out of use, or limited to special applications. The B cell was apparently once used in portable radios using valves (pre transistor days).
I can't recall their designations but I have not seen the once-common, larger size of rectangular 9V-battery for a long time. They were often used in portable transistor radios. The small version (PP 9 I think) is still plentiful, used typically in smoke-alarms.
I have a compact l.e.d, head-lamp which can take a so-called "camera battery", designated CR17345 or 123 depending which bit of the label you read. This is of AA diameter but about 2/3 its length; and 3V instead of 1.5. An extension-tube allows using a standard AA cell with some loss of light output - but cheaper!