Roughly measure vacuum pressure without sensor

How would you identify various levels of vacuum, without a calibrated, dedicated vacuum/pressure sensor? For instance, my understanding is that a Crooke’s Radiometer only works in certain ranges of vacuum. Liquids boil at temperatures different from normal, high voltages exhibit different behaviors and appearances (and cease) at different pressures, and so forth.

An ideal answer might be a table or annotated scale mapping vacuum ranges to different phenomena and vice versa, perhaps including links to demonstrations of said phenomena (though such should be fairly easily googled). The broader the range of identifiable vacuum, the more phenomena given, and (to the extent possible) the finer the "resolution" of identification, the better. (Less credit, but still some, given for tests requiring extremely rare and hard-to-come-by materials or equipment.)