I've used palette knife now and then for various paintings, usually to drag a highlight over a darker colour,
or to paint textured rocks, as in this painting, based on rocks & spray along the Moray Firth...
I began with the rocks, and let them dry before using the knife again to give the effect of waves splashing up and spilling out all over the rocky surfaces in the foreground.
Last week I decided to have a go with a larger palette-knife painting,
based on cliffs seen whilst walking along the Dorset coast.
This time I painted the whole picture with palette-knives... not a brush in sight.
Its all painted "wet-in-wet" too...and now just drying before adding final highlights...
perhaps after watching some Wimbledon tennis !
Here is a preview detail: