Among blazars, active galactic nuclei whose relativistic jet is pointing towards us, extremely high synchrotron peaked (EHSP) blazars are the least luminous but most energetic ones, with synchrotron peaks reaching frequencies of $\nu_{\rm sync} > 10^{17}\,$Hz. They represent the end of the `blazar sequence', poorly characterized so far due to limited statistics. The number of known sources of this class is still only a few dozen, yet they are critical to understanding acceleration processes in jets and non-thermal emission mechanisms. In this work, we search for EHSPs within a selection of 657 high-synchrotron-peaked (HSP, $\nu_{\rm sync} > 10^{15}\,$) blazars and blazar candidates (BCU) from the 2BIGB catalog by studying the broadband spectral energy distribution (SED). We use archival public data from the Space Science Data Center (SSDC) SED Builder service to obtain the multi-wavelength broadband spectral energy distribution of the selected sources, as well as our own analysis of Swift-UVOT and Swift-XRT data to constrain the synchrotron component. After modeling their SEDs, we identify new EHSPs and analyze their structure, physical properties, and possible evolution in the context of the more general population of blazars.