FLATTEN function to flatten all the values from one or more ranges into a single column

FLATTEN.txt

FLATTEN = 

LAMBDA(array,

LET(
    rows,ROWS(array),
    columns,COLUMNS(array),
    sequence,SEQUENCE(rows*columns),
    quotient,QUOTIENT(sequence-1,columns)+1,
    mod,MOD(sequence-1,columns)+1,

    INDEX(IF(array="","",array),quotient,mod)

    )   
)