Which wildcard operators are supported in Segment Builder?
Looking through the posts returned by this search and having done some experimentation, I suspect the asterisk (*) character is the only one (i.e. "matches zero or more of any character").
However, my reason for asking is that the Comparison Operators for Segment help article makes reference to "wildcard operators" (in the plural) and the concept of "globbing" (which is much more extensive than the simple asterisk).
As per Adobe - There are three categories of operators which allows you to compare and constraint values using selected operators. There are three categories of operators: Standard, Data Warehouse, and Distinct Count.
The only supported wildcard character is the asterisk: *. If you need to search for *, you can escape it with a backslash.
Example: Suppose you have a page name called "My cool product". The segment rule "Page name matches My*product" will match the above page name. However, the rule "Page name matches My\\*product" matches only the page name "My*Product".