The list widget has Combo Box functionality, just toggle view property. Please note, for a combo box, the widget must be in a non-responsive area, so add a panel if you are working in a responsive mashup.
A check box widget of course provides the check box functionality.
If you had to have a Grid type of setup, you could use a Repeater mashup and basically build a mashup to represent a row and use the repeater to repeat that row for as many times as needed.
