Within Google Spreadsheets you can generate sets of related words. Suppose you wanted to get creative with group names, put three or more items that you thought went together, and Google Sets attempts to find more members of the set. For example, a set of "dog, cat, fish" would yield more animals. Here's how it works:
1) Type in at least 3 related terms.
2) Highlight the 3 terms and [hold Control + drag] or [hold Option + drag]