FreeCAD - An open-source parametric 3D modeler
Lychee Slicer - A POWERFUL AND VERSATILE SLICER FOR SLA RESIN 3D PRINTERS With Lychee, prepare your 3D models for 3D printing: define the best orientation, create supports automatically, or manually, preview before sending them to your 3D printer.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
AstroPrint - Slice, Store, and Print your 3D files from any web enabled device.
Onshape - Onshape is the first full-cloud 3D CAD system. It runs in a web browser and on any mobile device.
ChituBox - Slicer compatible with a wide range of DLP/LCD/SLA 3D printers.