Corner the Enemy. A tiered triangular shelf avoids the plumbing that has taken up most of the cabinet space. One on each side can help keep things organized. Another option is a roll-out under-sink drawer cleverly designed to glide right past pipes.
Put it in its place. Office desk organizers work well in these small spaces. Consider purchasing two three draw organizing containers (take measurements first)
Add a little Spice. “Spicy Shelf” is a stackable organizer. It expands and contracts to fit most spaces. It can be used for just about anything when space is limited.