Librarian - Townsfolk

You start knowing that 1 of 2 players is a particular Outsider. (Or that zero are in play.)

You have great information for the early game. Either you know an Outsider is between two players, or you know that none are in play. If it is the first, you can confirm another good player. If it is the second, you can reassure your team that there is no Drunk and that any Outsider claims are likely evil bluffs.
If you learned a character, try to confirm which of the players it is as soon as possible. You can do this by counting down and saying the character at the same time, or if you saw the Drunk, just telling your two pings that they may have false information.
Keep in mind that some Outsiders will be reluctant to come out, and that there can be good reason for that. If you saw the Damsel, for example, they may not claim to you even if you say you know its them. Take this in stride and assume your information to be correct. Protect your confirmed player as best you can - whether that’s keeping them alive or getting them killed safely!