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.