you can select multiple tabs by holding CTRL and click on tabs to select them individually.
another easier way is this: for example you have 10 tabs open and you want to select all of them at once, move your mouse pointer to the right most tab, hold CTRL + SHIFT and then click on it, you will see all of the tabs, from left to right, are selected.
last example: you have 10 tabs open, you want to only select tabs from #3 to #8. you move your mouse cursor to tab #3, hold CTRL and then click on it, next you move your mouse cursor to tab #8, hold CTRL + SHIFT and click on it, you'll see now you've selected only tabs from #3 to #8 (i.e tabs #1, #2, #9, #10 are Not selected).
I would up date this as far as edge goes to: move your mouse pointer to the right most tab, hold CTRL + SHIFT and then click on it, to move your mouse pointer to the LEFT most tab, hold CTRL + SHIFT and then click on it,
