As we all know that ns_hera has one big hologram where reads "System offline". I made textured holograms, but as they look like skewed block, it ain't much. Ns_hera's looks cool, and now I ask how it can be made?

is this the one in double res? Thats a model AFAIK

There is a render effect for brushes called 'Hologram' when used with transparent textures creates a good looking hologram texture.