This is a core block and thus available by default in Gutenberg WordPress editor. No download required.
The WordPress Spacer Block in Gutenberg allows you to add some space in between your content. This makes it easier to add extra space between two blocks or content. Unlike the separator block, it does not add any visual line or anything.
Spacer Block Features
The spacer block once added allows you to adjust its height via the draggable resizer control. It does not have any options in the toolbar. You can also adjust the height from the block sidebar settings panel.
An extra space added between two paragraphs easily.
You can easily adjust the space/height by dragging the blue dot.
The sidebar settings for the spacer block.