You know, we can never have enough sentiments, and if you want them in an other language than English, this can be tricky sometime.
Being from Germany, I struggle with this very issue, I am writing to friends and family in Germany, so I do prefer a German sentiment, if I have the choice.
That is why I put together as small list (in alphabethical order) with German online shops that sell or even produce German sentiment stamps. Some of them are rather big, so you get a lot of supplies, some are just Dawanda-Shops, with the sentiment stamps only. I do hope this is some help to some of you.