MACRO for searching column for a letter and Copy/Paste the row into new MASTER sheet

Maybe:

Sub cwitty22()
Dim ws As Worksheet
For Each ws In ActiveWorkbook.Worksheets
    If ws.Name <> "MASTER" Then
    ws.Range("X7:X" & ws.UsedRange.Rows.count + 1).AutoFilter 1, "X"
    ws.Range("A8:X" & ws.UsedRange.Rows.count + 1).SpecialCells(xlCellTypeVisible).Copy Sheets("Master").Range("A" & Rows.count).End(3)(2)
    End If
    ws.AutoFilterMode = False
Next ws
End Sub