We made a single material for the cells, and used several effects that we can toggle on and off to make variations. We also used 4 different models, and ended up with about 40 different cells, but there are many more possible combinations.

Astrocyte destruction effect using vertex paint to control the destruction progression.

Aside from the 3D geometry, we used cutouts with alphas for far away cells, planes with only the electric impulse effect for objects beyond the fog of war, and a flat color with noise for the background.

The electric impulse effect is driven by a vertex color mask for 3D cells, and a mask for the imposters.

Particles from some explosions get lerger, blurry and transparent based on the camera distance. It looks very nice on VR.
We got the idea from Klemen Lozar: https://twitter.com/klemen_lozar/status/963813970221064192?s=20