Four new BL Lac surveys: sampling new populations

The advent of large area deep radio and X-ray surveys is leading to the creation of many new BLLac samples. In particular, the ROSAT All-Sky, Green Bank and FIRST surveys are proving to be rich sources of new BLLacs. We will discuss the methods used in four in-dependent BLLac searches based on these surveys. Comparison of the broadband spectral energy distributions of these BLLac with those of previously known objects clearly points to the existence of a large previously unrecognized population of objects with characteristics intermediate between those exhibited by Low and High energy peaked BLLacs.