There are six main types of validation controls:-
RequiredFieldValidator: It checks whether the control have any value. It's used when you want the control should not be empty.
RangeValidator: It checks if the value in validated control is in that specific range.
CompareValidator: It checks that the value in controls should match the value in other control.
RegularExpressionValidator: When we want the control value should match with a specific regular expression.
CustomValidator: It is used to define UserDefined validation.
ValidationSummary: It displays summary of all current validation errors.