What have you heard that designers are using on a normal basis?
Paper and a pencil or Sketch app
To create simple prototypes I always go with Balsamiq or Paper and Pencil.
To build UI's, Sketch and Photoshop.
To validate UX of the UI, marvelapp or invision.
To create working prototypes, https://framer.com/
Personally, I think pen and paper is far quicker (and more fun) than Balsamiq. Then onto Photoshop.