Some kind ant surveyors pointed out several ants for me. Here are Carpenter ants (Camponotus spp.) -- both major and minor!; acrobat ants (Crematogaster coarctica) -- on a mariposa lily; and field ants (Formica, perhaps F. moki) -- in the nest, with eggs. Two other genera are in another collection: harvester ants (Messor andrei and perhaps Pheidole californica).
As always, please leave a comment if you know the ID or have something to add.