Rimfire cartridges are, for practical reasons, these days limited to what are ordinarily called .22s, so a .22 long, .22 short, .22 long rifle, .22 Magnum, and perhaps a few other cartridges as well. There's a .17 calibre rimfire, for instance. There are a handful of cartridges that are in common use today. Historically, there was a broad range of rimfire calibres, but today the market forces have compressed them to a relatively small number. These are generally lower power cartridges, the reason being that the design of the rimfire cartridge case is not as strong as a centrefire cartridge case and cannot withstand pressures as high. The nature of the design limits the rimfire calibres to relatively low energies.
On December 8th, 2022. See this statement in context.