How do I scale the enormously sized desktop icons on Ubuntu 18.04?
- Open Files (aka Nautilus)
Grid view: Change your icon view from "list" to "grid" first by clicking the button next to the hamburger menu.
- Zoom out: Click on the hamburger menu (three-horizontal-lined button at top-right) and decrease the icon size by clicking the "zoom out" button (or Ctrl+-).
This should also reduce the size of the icons in your desktop.
You can also resize icons by right clicking on each icons and select resize. Then you resize it up to a certain allowed minimum.
In case you have a wheel mouse
Open Nautilus and click on the show directory as symbols icon (middle of the button on the top-right of nautilus's window) an press Ctrl+Scroll Mouse up/down.