How can I find the Angler?

Any chance you have something that you can float in water (Ex: Slime Saddle or Water Walking Boots.) I have found him at the very end of the ocean floating where the map ends. Also there is a chance he moved into a sky island house or living wood house that you have discovered already.

He might have died before you got to the ocean he was at. Try building a suitable house for him to move into. I have had the same circumstance and this worked for me.

Sometimes you need to fish a bit to fish him up and he will come up. You also need a empty house for him to spawn. Check the surface of the oceans, and the beaches , and fish for him a lot. If he never come up there is a very slight chance he will spawn in the underworld.