Jeweler could be in a Kingdom with no way to gain cards... if it doesn't let you gain cards by itself, then it could be in a split pile with a card that gains cards, etc. Though if so it should also have +1 action (unless there's a village in that same split pile also).
Robber appears too harsh if there's no limit on it. You overbuild your engine so that you have $13 to spend but only 1 buy, so now you just have to skip your entire next turn?
Combine should probably just count
cost.
and
are each specific to 1 expansion, and not used in this expansion.
Comparing Labor Force to Storyteller, and then Caravan to Laboratory, it seems to me like Labor Force would be pretty much balanced if it also had +1 action... that should make it as close to Caravan in strength as Storyteller is to Laboratory. If I'm even close to right, it would be really weak as is.
Rackhouse feels like the wording should be reversed... since discarding a card is bad and removing tokens is good, you would generally think of it in terms of "discard a card to remove a token", not "remove a token to discard a card". I get that it's different in the case where yo have 0 cards in hand, but that seems like a pretty rare situation after resolving an action card.