Is there a known $n$ such that the number of groups of order $n$, sometimes denoted $\mathrm{gnu}(n)$, is equal to $33$?
This database goes up to groups of order $50000$ and $33$ is the smallest number that never appears in the "total" column. Note that where the total column is empty is where the number of groups is currently unknown because it'll be incredibly large (orders like $2048, 3072, 4096, 4608, \dots$).
So such an $n$ must be greater than $50000$.
This question is dealt with in the paper Counting groups: gnus, moas and other exotica, where the minimal answer is listed as unknown. Perhaps there has been a development since? Indeed, it also lists the minimal answer for $31$ as unknown, whereas $11774$ is now known to be the minimal such order, which happened to be their guess. Perhaps their guess $163293$ is known to work for $33$, perhaps it is indeed the smallest such $n$?
Yes, the number of groups of order $163293$ is indeed $33$. Since $163293$ is square-free, $\operatorname{gnu}( 163293 )$ can be computed using a formula due to Holder. I do not know if it is the smallest $n$ for which $\operatorname{gnu}(n) = 33$, however. It is the smallest value for which Maple can compute an answer equal to $33$, but there are many values of $n$ less than $163293$ for which Maple cannot compute $\operatorname{gnu}(n)$.