Pretty much an echo of the general lists i've been seeing above (torture, murder, theft, overall destruction of property, lying, *insert more spy/military expected stuff*)
i will say there are some slight particulars to the two "heavier" ones; clio has killed a lot of people and maimed/tortured more. Though she does not count that as a sin....honestly, it gives her a sadistic thrill. she's better about controlling it to ensure she doesn't go past "what's necessary" but the feelings are still there.
There's only a handful of things she's regret in her life, but one of her most prominent ones was not being the one to kill someone specific from her past.