This is an extremely simple mod that makes dragons you encounter non-aggressive to the player. For lore reasons, I left the other faction relationships alone, so guards and other NPCs will still attack spawned dragons and certain followers may as well. The opposite holds true, as well, so dragons will still attack towns and such when they spawn nearby. They're neutral, though, so you can still aggro them with magic, arrows, or shouts. Dungeon specific and quest related dragons should still be aggressive, to avoid messing up any quests. Dragons spawned from miscellaneous quests, such as those given by the jarls, will most likely be non-aggressive, however, so you'll need to attack them to draw their attention.

I had the idea for this mod because I was annoyed by the constant dragon encounters after finishing the main quest line. I'd like to make an additional version of the mod that activates automatically after finishing the MQ eventually, but haven't figured out how to do so quite yet. If anyone badly wants a version of the mod with entirely unaggressive dragons that don't attack any cities or NPCs, aside from groups like the bandits and forsworn, just let me know and I'll consider making that an alternate version. For now, I suggest activating this mod after finishing the main quest line, particularly if you let a certain dragon live.

Update 1: Added, by request, a version that makes dragons non-aggressive to all potentially friendly factions. Groups like the Forsworn and bandits are still considered enemies, however.

Update 2: This mod is now included in the Gameplay Enhancements Mods for Skyrim list.