  We provide two types of guessing principles for ultrafilter
($\diamondsuit^{-}_{\lambda}(U), \ \diamondsuit^p_\lambda(U)$) on $\omega$
which form subclasses of Tukey-top ultrafilters, and construct such
ultrafilters in $ZFC$. These constructions are essentially different from
Isbell's construction \cite{Isbell65} of Tukey-top ultrafilters. We prove using
the Borel-Cantelli Lemma that full guessing is not possible and rule out
several stronger guessing principles e.g. we prove that no Dodd-sound
ultrafilters exist on $\omega$. We then apply these guessing principles to
force a $q$-point which is Tukey-top (answering a question from
\cite{Benhanou/Dobrinen23}), and prove that the class of ultrafilters which
satisfy $\neg\diamondsuit^{-}_\lambda$ is closed under Fubini sum. Finally, we
show that $\diamondsuit^{-}_\lambda$ and $\diamondsuit^p_\lambda$ can be
separated.
