Design for 3d printing can reduce parts count
Traditionally, fixtures can be composed of many pieces, so one very simple way to leverage the freedom of design that 3d printing allows is to consolidate assemblies into a single part.
If reproducing an existing tool, start with a redesign that consolidates as many components as possible into one piece. If designing a new item, create it as one piece. Only split off parts when it is advantageous to the operation of the fixture. Integrating parts into a single component has many advantages including reducing tolerance stackups and eliminating assembly time.