  We report on our progress in studying exotic, heavy tetraquark states,
$qq\prime \bar Q\bar Q\prime$. Using publicly available dynamical $n_f =2+1$
Wilson-Clover gauge configurations, generated by the PACS-CS collaboration,
with pion masses $\simeq$164, 299 and 415 MeV, we extend our previous analysis
to heavy quark components containing heavier than physical bottom quarks $\bar
Q\bar Q\prime=\bar b\prime\bar b\prime$ or $\bar Q\bar Q\prime=\bar b\bar
b\prime$, charm and bottom quarks $\bar c\bar b$ and also only charm quarks
$\bar c\bar c$. Throughout we employ NRQCD and relativistic heavy quarks for
the heavier than bottom, bottom and charm quarks. Using our previously
established diquark-antidiquark and meson-meson operator basis we comment in
particular on the dependence of the binding energy on the mass of the heavy
quark component $\bar Q\bar Q$, with heavy quarks ranging from $m_Q=0.85\ldots
6.3\cdot m_b$. In the heavy flavor non-degenerate case, $\bar Q\bar Q\prime$,
and especially for the tetraquark channel $ud\bar c\bar b$, we extend our work
to utilize a $3\times 3$ GEVP to study the ground and threshold states thereby
enabling a clear identification of possible binding. Finally, we present
initial work on the $\bar Q\bar Q\prime=\bar c\bar c$ system where a much
larger operator basis is available in comparison to flavor combinations with
NRQCD quarks.
