My first thing, a simple kitchen organiser ideal for the brushes and bottles by the sink. Needs a 290mm wide print bed. It was mainly my first exercise in 3D modelling, drafted in OnShape, the CAD files are here (public to all OnShape users, sign up for a free account): -

https://cad.onshape.com/documents/9e55d1f998bf316e4dcad38e/w/87a83a85c5e69faadf93fb37/e/8de9cbe2b973303ad840b366