How TVSS works ?

They work by shorting out voltages above the design voltage. An ordinary electrical outlet will arc and short at 1000 volts. Varistors are back to back zener diodes that close at a design voltage shorting out anything higher. I am less acquainted with the plasma arc ones. I will suggest moving this to the E&L forum where you should get more information.

As Labman said ZNR's are back to back Zener diodes or what I might call a power Zener diode. The reverse breakdown of a diode can be taylored. The mechanism is Zener or Avalanche breakdown. This reverse breakdown is exploited in Transient Voltage Suppressors (e.g Transorb, ZNR). They effectively regulate at the breakdown voltage. They can destructively short or open when subjected to severe transients. They usually short.

Spark gaps are also used. These use the dialectric property of air and a specific spacing that sets. These devices actually arc or short out at some specific voltage.

Filters made from capacitors and inductors can remove RF (Radio Frequency) superimposed on a lower frequency like 60 Hz. The voltage across a capacitor cannot change instantaneously. The current through an inductor cannot change instantaneously.