CAP stands for Civil Aviation Publication and many are, as you say, similar to FAA AC's. CAPs are just the registration system for issuing advisory notices, explanatory notices. information from studies, etc.
However, British Civil Aviation Regulations (BCARs) are also CAPS and similar to EASA regulations but only pertaining to British aircraft and organisations not covered by EASA regulations i.e. State aircraft (including Coastguard and Police Units) unsupported aircraft types such as Westland-Bell 47 helicopters and Supermarine Spitfires, etc. again, on the British register.
Some other countries also base their airworthiness regulations on the British CAA's BCARs and CAPs.
I suggest that you browse the CAA publications (caa.co.uk/publications)