Hello there!
Not sure if these will help since it does kind of depend on what type of power/authority you’re trying to explore but here you go.
ACT 1 Scene 2 - “Your beauty was the cause of that effect: Your beauty, that did haunt me in my sleep” —> anaphora of ‘your’ (power over Anne through appeal)
ACT 2 Scene 4 - “the tiger now hath seized the gentle hind” —> metaphor, animal imagery, symbolism (comparing Richard to a tiger - powerful creature)
ACT 4 Scene 4 - too much to put all here but there are lots of good examples of stichomythia there particularly with Elizabeth and Richard
e.g.
(Richard) “as long as heaven and nature lengthens it”
(Elizabeth) “as long as hell and Richard likes of it” —> short, sharp sentences showing how Elizabeth and Richard meet at an equal level of power through their use of words (words through this technique are demonstrated to be like powerful weapons that can be used against others)
Though I don’t have much on this one sorry, I suggest to also take a look at Act 5 with Richmond in it, there are plenty of places for comparison in which you can show the difference between the way Richard handles power and authority (more cruel and negatively) compared to Richmond handling power and authority (more positively). Maybe you can even mention the set up of the act and how Shakespeare purposely - in the beginning - cuts between Richmond and Richard’s scenes!
