Horst Schaeffer's Calendar window can be sized to display up to 12 month (any width/height ratio). The month range can be shifted step by step. Click on month or year caption to select any month or year.
Quick toggle: full year / custom layout.
The selected date (first button) or the current date and/or time (second button) can be copied to the clipboard. The date/time formats are selectable by menu (four default formats; up to 10 custom formats for each button can be assigned in the INI file).