sRGB
The standard colour space for the web and almost everything else — limited, old, and universal precisely because of it.
HP and Microsoft defined it in 1996 from what the CRT displays of the day could actually manage. The ambition was not to cover every visible colour but to have everyone start from the same assumption, so an image looked roughly the same everywhere.
It succeeded so well that the space has become hard to leave. If an image lacks a colour profile, sRGB is assumed, and that assumption is right in the vast majority of cases. The downside is that it does not reach the saturated greens and cyans modern displays can produce — a Display P3 image shown as sRGB looks oversaturated, and the reverse looks washed out.