How many quests can you find on other quests?

Very occasionally on daily/weekly quests you can find a new quest in a container.

So far I have found two: "Vault 789" and "With Friends Like These".

Both gave multiple legendary rewards. Are there any more?

2 Answers

The Fallout wiki lists five.

So looks like I've got a few more years of daily quests to unlock them all.

"Vault 789" and "With Friends Like These" are single-stage quests. These quests typically reward better items than daily or weekly quests.

Here's a link for all of the quest types.

SPOILERS -- Fallout Shelter Quests Wiki