
A highly regarded expert |

Big as they can be, it seems dragons don't swallow you whole. I suppose they like to peel you gently out of your armor to savor your soft, gooey center and crunchy limbs. They swallow people whole in the movies, but not in PF.
Other monsters do just down you in one gulp. I find it hilariously funny when adventurers go sliding down a gaping gullet. It's something every character should experience in their career. Problem is, there don't seem to be that many monsters that have the "swallow whole" ability.
Is there a list? Can you help me make one? I'd hate for my players to miss out on the fun of being inside a purple worm, or some other creature that says "I want ya in mah belly!" wondering why they didn't bring a light slashing or piercing weapon.
Purple worm
Behir
What else?

Astral Wanderer |

Other than those already said...
Bestiary 1:
Giant Frog, Froghemoth, Gibbering Mouther (Engulf), Neothelid, Remorhaz, Sea Serpent, Dire Shark, Shoggoth (Engulf), Tarrasque.
Bestiary 2:
Charybdis, Olethrodaemon (Drain Soul), Handmaiden Devil (Tentacle Cage), Tylosaurus, Dust Digger, Giant Gar, Moonflower (Pod Prison), Mu Spore, Nightcrawler, Nightwave, Giant Toad, Glacier Toad, Giant Snapping Turtle, Water Orm.

Groggie |

Is there a list? Can you help me make one? I'd hate for my players to miss out on the fun of being inside a purple worm, or some other creature that says "I want ya in mah belly!"
....
What else?
Gelatinous Cube doesn't say the words "Swallow Whole" but effect is the same from its "Engulf" ability; characters end up inside the critter.
BTW: Cubes are awesome at the bottom of a pit. :)