Concept:
Superconductors are materials that show zero electrical resistance below a certain critical temperature.
Step 1: Ordinary conductors have small but finite resistance.
Step 2: Semiconductors have conductivity between conductors and insulators.
Step 3: Insulators have very high resistance.
Step 4: Superconductors show zero resistance below their critical temperature.
Therefore, materials having zero electrical resistance are:
\[
\boxed{\text{Super conductors}}
\]