Gessoing panels and canvas
Oil-based gessoes on canvas require a sizing before applying. Rabbit skin glue is traditional, but you can use GAC 100 or PVA size, too. Acrylic gessoes and pastes don’t require sizing and can be applied directly. Brushes, rollers and trowels are all useful for gessoing.
Standard housepainting brushes are cheap and excellent for applying gesso. Thicker gessos can be applied with a spatula. I bought this one on Amazon in the Kitchenware section. Putty and spackling knives are handy for producing a variety of textures when applying heavier acrylic gels and pastes.