Ttk's checkbutton widget.
Mat To remove the indictator and have your checkbuttons look like normal buttons, use a custom style:
# 1. create a new style "MatButton" based on the default style for checkbuttons
ttk::style configure MatButton.TCheckbutton
# 2. use the same layout, that normal buttons use
ttk::style layout MatButton.TCheckbutton [ttk::style layout TButton]
# 3. our style should adjust its relief to reflect the select state
ttk::style map MatButton.TCheckbutton -relief {selected sunken !selected raised}
# and we're done.. create a new checkbutton and enjoy :)
pack [ttk::checkbutton .b -text "Check Me" -style MatButton.TCheckbutton]