In this grasshopper example file you can create many different voxelized lattice structures by using the AxoloTL plugin.
In this grasshopper definition by Mathias Bernhard, you can create an iso-surface from the intersection between a sphere and Metaballs and use the Axolotl plugin to convert them into a voxelized form.
This grasshopper definition creates a voxelized ramp by using the AXOLOTL plugin. You can change the parameters to generate different designs.
In this grasshopper definition, you can create a parametric voxelized node by using the AXOLOTL plugin.
In this grasshopper definition, you can create a voxelized shell shape by subtracting two volumes and finally model a Triply Periodic Minimal Surface.
In this grasshopper definition you can create a 3d sine iso surface by using the Axolotl Plugin.
AXOLOTL by worbit provides a set of components for volumetric modeling in Rhino Grasshopper. They work based on the principle of signed distance functions (SDF).