FrontEndDynamicExpression is a global front end option that specifies an expression to be dynamically updated whenever the front end is running.

CellDynamicExpression is an option for cells that specifies an expression to be dynamically updated whenever the cell is visible on-screen.

CheckboxBar[x, {val_1, val_2, ...}] represents a checkbox bar with setting x and with checkboxes for values val_i to include in the list x.CheckboxBar[Dynamic[x], {val_1, ...

StatusArea[expr, string] displays string in the status area of the current notebook when the mouse pointer is in the region where expr appears.

SynchronousUpdating is an option for Manipulate, Dynamic, and related functions that specifies whether or not to evaluate their contents synchronously.

Initialization is an option for Dynamic, DynamicModule, Manipulate, and related constructs that specifies an expression to be evaluated when the construct is first used or ...

DynamicMomentumIndex

TrackedSymbols is an option to Refresh, Manipulate, and related functions that specifies which symbols should trigger updates when their values are changed.

Animator[u] represents an object that displays with the value of u being continually increased from 0 to 1 with time. Animator[u, {u_min, u_max}] makes u vary from u_min to ...

Mouseover[expr, over] represents an object that displays as over when the mouse pointer is over it, and as expr otherwise.