Return the serial number of a particular date

=DATE (year, month, day)

Return the serial number of the current date

=TODAY()

Returns the character specified by a number

CHAR(number)

Return the largest value in a range of values

MAX(number1, [number2], ...)

Return the logical value TRUE if a cell is blank or empty

=ISBLANK(value)

Return the serial number of the current date and time

=NOW()

Return a list of unique values in an array or range

=UNIQUE(array,[by_col],[exactly_once])

Extract characters from the beginning or end of a string.

LEFT(text, [num_chars]), LEFTB(text, [num_bytes])

RIGHT(text, [num_chars]), RIGHTB(text, [num_bytes])

Replace one or many instances of specific text based on its content (not on its position).

SUBSTITUTE(text, old_text, new_text, [instance_num])

Return the relative position of a specified item in a range

=XMATCH(lookup_value, lookup_array, [match_mode], [search_mode])

Search one row or one column (or an array) for a value

(Vector form) =LOOKUP (lookup_value, lookup_vector, [result_vector])

(Array form) =LOOKUP(lookup_value, array)

Return the logical value TRUE if the cell contains any value that is not text.

=ISNONTEXT(value)

Repeat a specific text string by a number of instances.

REPT(text, number_times)

Return the logical value TRUE if the cell contains either a TRUE or FALSE statement.

=ISLOGICAL(value)