Dynamically Tagged Groups of Metal-Poor Stars from the Best \& Brightest
  Survey
  Orbital characteristics based on Gaia Early Data Release 3 astrometric
parameters are analyzed for ${\sim} 4000$ metal-poor stars ([Fe/H] $\leq -0.8$)
compiled from the Best $\&$ Brightest survey. Selected as metal-poor candidates
based on broadband near- and far-IR photometry, $43\%$ of these stars had
medium-resolution ($1200 \lesssim R \lesssim 2000$) validation spectra obtained
over a seven-year campaign from $2014$ to $2020$ with a variety of telescopes.
The remaining stars were chosen based on photometric metallicity determinations
from the Huang et al. recalibration of the Sky Mapper Southern Survey.
Dynamical clusters of these stars are obtained from the orbital energy and
cylindrical actions using the \HDBSCAN ~unsupervised learning algorithm. We
identify $52$ Dynamically Tagged Groups (DTGs) with between $5$ and $21$
members; $18$ DTGs have at least $10$ member stars. Milky Way (MW)
substructures such as Gaia-Sausage-Enceladus, the Metal-Weak Thick-Disk,
Thamnos, the Splashed Disk, and the Helmi Stream are identified. Associations
with MW globular clusters are determined for $8$ DTGs; no recognized MW dwarf
galaxies were associated with any of our DTGs. Previously identified dynamical
groups are also associated with our DTGs, with emphasis placed on their
structural determination and possible new identifications. Chemically peculiar
stars are identified as members of several DTGs, with $6$ DTGs that are
associated with \textit{r}-process-enhanced stars. We demonstrate that the mean
carbon and $\alpha$-element abundances of our DTGs are correlated with their
mean metallicity in an understandable manner. Similarly, we find that the mean
metallicity, carbon, and $\alpha$-element abundances are separable into
different regions of the mean rotational-velocity space.
