ListSessions is a free tool that lists sessions (All/Active/Disconnected) and clients machines connected in your Citrix farm. List Client Information option will list all Clients connected to Citrix Farm with Client Options selected. You can use Save Report (TXT) option to generate a Text file with the Lists of Sessions or List Client Information.
The Save Report Clients (XLS) option will generate an Excel file with Client Options selected.
Search Session ID option will locate the username with a specified Citrix Server/Session ID