The answer is 'referent power'.
An example might be a long-standing employee who 'knows the ropes' and helps others. Or it may be a famous person whose fame gives them power.
In some sources this may be known as 'charisma power'.
For me a great example of this form of power is Bill Clinton, who combined his allegedly substan-tial charisma, along with legitimate power and informational power. Presumably as US President, he also had access to coercive power as well as reward power. A powerful guy in a powerful position. People who have dealt with him long after he ceased to be the President say that his referent / cha-risma power lives on, hugely.