The little cabinet to the the left of the refrigerator was a tiny life-saver for us. It gave more storage storage in the tiny kitchen without blocking access to the existing narrow attic door. We bought regular sized cabinets and then cut the backs off to make them more shallow. We cut them down on a table saw, and of course each of the shelves had to be cut down too. It was a fairly quick job. 
They were attached directly to the wall without backs. Because of their size they were very stable. The depth was seven inches, which fit all kinds of things. We filled it with large mason jars, olive oil, vinegar, peanut butter, maple syrup, and of course a few spices. It added so much. 
Another creative cabinet, shown below, was a wall cabinet that we put on the floor. It allowed extra storage without interfering with the walking path. Initially we put a pretty wood cutting board on top of it, but did not end up loving the look. The granite company was all to happy to sell us a little matching piece of granite to put on top. 
Another helpful solution in the kitchen was base cabinets with drawers. It’s fairly conventional and allows so much more useful storage than the more typical doors and shelves. That set up ends up involving squatting or kneeling and dragging things out from the back at times. With drawers, even the lowest ones let you see what you have and access it easily. We used the four lower drawers in this set of cabinets to hold food, pots and pans, mixing and storage bowls, and tea towels. It’s a little more money for drawers, but so much more functional. 
In the living room we found a little second hand toy storage chest. It allowed extra seating and storage without shrinking the room too much. A remarkable number of things ended up in that bench– paper, the scanner, the printer, blankets, and little odds and ends. 
American Tiny 