First class letter: first class stamps

Unexpectedly, a letter arrived out of the blue, the second packet for exchange from Thomas in Sweden. As like last time, the envelope was covered with stamps on the front and on the reverse (and a prioritaire first class sticker). It would have been fitting had there been 30, as the envelope is the 30th with stamps that I'm exchanging. In fact, there were 35 - and another block of 50 on the back!

Looking back, I realize that this is the second half of the original exchange. I'd sent double the number of NZ stamps (100) against the first batch of 50. Nevertheless, with Thomas's extra postage I feel that I'm in a position of obligation.

 

Thomas apologizes for sending more Swedish stamps. He doesn't need to. The stamps he encloses here include some of the best engraved stamps I've ever seen. Take a look at the 13 stamps below. What's the word for 'wunderbahr' in Swedish?