There's a little + that you can click on the icons.
Or, you can use the keyboard arrows and spacebar.
Not sure if there's others.
Edit: Just found another one actually. Middle-clicking selects without opening.
This works better than the little + on the icons because the + behaves like a "ctrl-click."
personally, I don't like the plus icons (I'd prefer it if they were simple checkboxes), so any one of:
(mouse-only) drag a selection box from an empty area
(mouse-only) right click directly, already opening the context menu to copy, cut, rename, share, etc - which is often the goal when selecting a single item.
I've always used the little plus sign on icons. It's ingrained into my brain. I even did the same on windows before switching to Linux 6 years ago. Single click and the little check box on Windows.