In the JavaFX Scene Builder there is a text field to search in the library:
Is this a default control (if so I can't find it) or did they simply style a text field?
I tried looking in the source code of the Scene Builder as well, but could not find it.
There is no premade control to work this way, but you can create one using TextField events.
For example see next code: AutoComplete ComboBox in JavaFX