3D printing can add a lot to hydroponics (and about every for of gardening for that matter). On this page, I have all the things I have 3D printed parts to aid my hydroponics and plants. There may not be much now, but this page will (hopefully) expand over time with new, better and more useful 3D printed parts.
On of the things that you will need to do with most larger plants is support them. Plants like tomatoes can grow incredibly large, but can only support themselves for around a meter. To make the plant grow larger, the plant is tied to some sort of trellis or wire. This is where the trellis clamp comes in. It clamps itself to a wire and forms a supporting ring for any plant.
The trellis clamp prints in 2 equal parts that can be folded together. There are two sides to the clamp. The longer side grabs on to the wire, the shorter side simply clamps to the clamp. To use the clamp, hang a wire above the plant. At the height where the plant needs support, fold the two clamp halves together. Now the clamp is firmly on the wire and supporting the plant.