How to see which quests are done

[Arethor]

It won't help you with missions you've already completed but I'd suggest getting QuestHistory. It keeps track of every quest you initiated and the status of it. Whether you completed it, abandoned it, or whether it's still active. It also gives you some helpful information like the coordinates of the NPC that initiated the quest so that you can find them again.

Like I said, it will only have the information for the quests you currently have, and the quests you get in the future, but it's still a good tool to have.