You can view all formulas by changing the View options, menu command Tools/Options/View and tick the Formulas checkbox in the Window Options section ( shortcut to toggle Formulas is Ctrl-' ( that's Ctrl key and the left single quote that is to the left of the 1 key on a UK keyboard ).
To filter on formula you'd need an extra column to contain the text of the formula, and that would have to be generated by VBA, or a VBA User-defined Function, or a Defined Name macro formula. I'd use the Defined Name macro formula ... Insert/Name/Define, CellLeftFormula with a definition of =GET.CELL(6,cell_ref_cell_left_of_current_cell)
which will show the formula of the cell to the left of the cell where =CellLeftFormula is entered. Then you can filter on that column.
Cheers, Glenn.
Beauty is in the eye of the beerholder.