Aven is used as a surname in various countries across the globe, and occasionally as an Anglicized variant of the Irish girl name, Aoibheann. In the US, Aven only started to see significant use in the 2000s, and over the next two decades, it has slowly risen in popularity.

Friso is a name that refers to Frisian person living in the Dutch province of Friesland. The name has become more popular in recent years as it was used for a member of the Dutch royal family, making it one of the more adventurous royal baby names.

A form of Heinrich or Henrike (Henry in English), as well as of their feminine counterparts. Now most commonly feminine, but certainly an attractive choice for either sex.

Gerard, Gerry, and Jerry may be so far out they may never come back in the U.S., but Jerry-equivalent Jurre is a Top 100 name in The Netherlands.

Nine is not a numerical name, but rather a Dutch nickname for Katherine. It's identical in sound to Nina, although the two are etymologically unrelated.

A form of Heinrich or Henrike (Henry in English), as well as of their feminine counterparts. Now most commonly feminine, and especially popular for girls in Germany in the 1960s and 1970s. Famous bearers include German actress Heike Makatsch and athlete Heike Drechsler.

Elizabeth is a name of hundreds of variations, but this German name for girls, redolent of the Olde Country, is unfamiliar in the U.S. and likely to remain so.