Open Rights Group, a UK-based organisation focussed on privacy and free speech run blocked.org.uk, does something like this for UK ISPs. They provide Raspberry

Open Rights Group, a UK-based organisation focussed on privacy and free speech run blocked.org.uk, does something like this for UK ISPs. They provide Raspberry Pis which people run from their networks. The devices perform regular requests to various sites to check if any are blocked.