Many characters are illlegal in file and folder names, e.g. \ / : * ? " < >
C:\ is a drive, plus root folder contents.
C: is a drive.
Typical usage of Regex in various applications consider a "/" forward-slash as the beginning of a regex, and a "/" forward-slash as the end.
If at all possible, the addition of Regex for QuickSearch, QuickFilter would be great, it could be indicated by starting the QuickSearch or QuickFilter with a forward-slash, e.g.
/FOO.BAR
which would be similiar to (if QuickSearch or QuickFilter supported glob)
*FOO?BAR*