What is an example of a surname formed by combining two single-character family names?

Question

There are many origins of compound surnames. Some derive from royal or official titles, place-names, professions, while others originate from non-Han Chinese clans that lived in ancient China or were simply created by combining two single-character family names.
_{101 Most Common Surnames in China and Their Meanings (2022)}

I'm interested in the claim in bold, since I haven't encountered such a 2-character family name before. It reminds me of how (with English names) some people take on hyphenated surnames when getting married, or give such names to their children.

Question: What is an example of a surname formed by combining two single-character family names?

Answer 1

Below is a list of frequently encountered Chinese Compound Surnames (复姓). The name with boldface represents those with both of the letters in the name are Chinese surnames.

欧阳, 令狐, 皇甫, 上官, 司徒, 诸葛, 司马, 宇文, 呼延, 端木, 张简, 范姜, 周黄, 江谢, 司空, 西门, 独孤, 东方, 鲜于, 东郭.

百家姓(One Hundred Family Names)收录了60个复姓:

万俟、司马、上官、欧阳、夏侯、诸葛、闻人、东方、赫连、皇甫、尉迟、公羊、澹台、公冶、宗政、濮阳、淳于、单于、太叔、申屠、公孙、仲孙、轩辕、令狐、锺离、宇文、长孙、慕容、鲜于、闾丘、司徒、司空、亓官、司寇、子车、颛孙、端木、巫马、公西、漆雕、乐正、壤驷、公良、拓跋、夹谷、宰父、穀梁、段干、百里、东郭、南门、呼延、羊舌、微生、梁丘、左丘、东门、西门、南宫、第五。

Answer 2

What is an example of a name formed by combining two single-character family names?

In Chinese culture "name" is not equal to "surname". If I interpret your question as “surname formed by combining two single-character family names”:

“申屠”, “夏侯”, “張簡”, “范姜”, . . .

Answer 3

What you're looking for is called 雙姓, which is different from 複姓。

雙姓is formed by combining two family names. Examples are 王曹、范姜、張簡, etc. These are typically formed from marriage between 王 and 曹、范 and 姜、張 and 簡, etc.

冠夫姓, e.g. 林鄭月娥, is a special case of 雙姓. This is formed by adding husband's surname to wife's name when she gets married. This is a result of the influence of western culture. As opposed to 雙姓, this typically doesn't pass along to descendants.

複姓, on the other hand, is not derived from marriage and the two characters each may not be surname at all. For example, 夏候 is derived from 夏, the surname, and 候, the name of the official position, 候爵。Others such as 宇文、慕容、上官、西門、令狐, etc. might have non-Han origin.

Wiki has a page for 雙姓 and another for 複姓。