  We predict several new exotic doubly-heavy hadronic resonances, inferring
from the observed exotic bottomonium-like and charmonium-like narrow states
$X(3872)$, $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$, and $Z_c(4020/4025)$. We
interpret the binding mechanism as mostly molecular-like isospin-exchange
attraction between two heavy-light mesons in a relative S-wave state. We then
generalize it to other systems containing two heavy hadrons which can couple
through isospin exchange. The new predicted states include resonances in
meson-meson, meson-baryon, baryon-baryon, and baryon-antibaryon channels. These
include those giving rise to final states involving a heavy quark $Q=c,b$ and
antiquark $\bar Q' = \bar c,\bar b$, namely $D \bar D^*$, $D^* \bar D^*$, $D^*
B^*$, $\bar B B^*$, $\bar B^* B^*$, $\Sigma_c \bar D^*$, $\Sigma_c B^*$,
$\Sigma_b \bar D^*$, $\Sigma_b B^*$, $\Sigma_c \bar \Sigma_c$, $\Sigma_c \bar
\Lambda_c$, $\Sigma_c \bar \Lambda_b$, $\Sigma_b \bar \Sigma_b$, $\Sigma_b \bar
\Lambda_b$, and $\Sigma_b \bar \Lambda_c$, as well as corresponding S-wave
states giving rise to $Q Q'$ or $\bar Q \bar Q'$.
