  We show that there are infinitely many distinct closed classes of colimits
(in the sense of the Galois connection induced by commutation of limits and
colimits in Set) which are intermediate between the class of pseudo-filtered
colimits and that of all (small) colimits. On the other hand, if the
corresponding class of limits contains either pullbacks or equalizers, then the
class of colimits is contained in that of pseudo-filtered colimits.
