Your starting seven and the first two hard-coded migrant waves are all you get!

No diplomatic caravans from the mountainhome, your dwarves will never declare themselves monarchs. Trading with other civs can still occur, although I didn't have any luck generating such a world.

Great for a low-stress hermetically sealed fortress. True extinction status can be verified by viewing a blank "civilizations" screen during the very start of your fortress.

Rebuild civilization the traditional way or pass on your cultural legacy through citizenship petitions.

World Notes:

LOTS of goblins and kobolds, no friendly civilizations. You can probably still get goblin and animal men petitioners while not having to worry about trading with other civs.