"Simple" Alternatives toSU(6)

A search is made for simple classical Lie groups which could serve as alternatives to $\mathrm{SU}\left(6\right)\mathrm{}$. Among the groups with less than 140 generators, the most likely possibilities are found to be $R\left(11\right)\mathrm{}$, with 55 generators, and $\mathrm{Sp}\left(16\right)\mathrm{}$, with 136 generators; but even these two have features which seem to discriminate against their use as particle symmetry groups.