I wish/If only + Past perfect
I wish I had come to your party!
I wish I had worked harder.
If only I hadn’t eaten so much.
If only I had driven more carefully.
I should have (not) + Past Participle
I should have come to your party.
I should have worked harder.
I should haven’t eaten so much.
I should have driven more carefully.
I regret +Noun/V-ing
I regret not coming to your party.
I regret not working harder.
I regret eating so much.
I regret leaving you alone.
I regret the things I didn’t do when I had the chance.