Hidden Element : it is a tool in Revit that is used to hide a element or category of an object , not permanently.
Leaderline: a leaderline in Revit refers to a line added to connect a text to an object.
Section: refers to an area or hidden part of an object cut away or removed some of that object.
Light bulb: It reveals hidden elements and you can unhide in view element.
Weephole: refers to where water is being let out.
Cork: refers to a seal.