The Excel function: ISFORMULA
Returns TRUE if there is a reference to a cell that contains a formula.
More information: support.microsoft.com/en-us/office/isformula-function-e4d1355f-7121-4ef2-801e-3839bfd6b1e5
Other functions
Returns information about the formatting, location, or contents of a cell
Returns a number corresponding to an error type
Returns information about the current operating environment
Returns TRUE if the value is blank
Returns TRUE if the value is any error value except #N/A
Returns TRUE if the value is any error value
Returns TRUE if the number is even
Returns TRUE if the value is a logical value
Returns TRUE if the value is the #N/A error value
Returns TRUE if the value is not text
Returns TRUE if the value is a number
Returns TRUE if the number is odd
Returns TRUE if the value is a reference
Returns TRUE if the value is text
Returns a value converted to a number
Returns the error value #N/A
Returns the sheet number of the referenced sheet
Returns the number of sheets in a reference
Returns a number indicating the data type of a value