Where are all possible places to use lockpick?

Question

Is there any use for it apart from thieves guild quest? Found some info on latino sites but im having really hard time translating it with google.

Comments

I've tried them on several locked doors  that have no keys, or no discoverd keys atleast with no succes,
So far, all info I can find about them on fansites and by playing the game, is that they're only used in the hieves guild quest.
On that sturdy chest, and to steal Theodore's fish.