Until recently, pressing spacebar toggled expanding my photos in Photos, and single keys provided a way to edit photos (e.g. C for crop). None of these features now work for me.
How do I restore keyboard shortcuts in Photos?
Since MacOS Mojave, Photos have changed shortcuts. I used Space key very extensively, so made work again (link):
Also few useful shortcuts:
Also check cmd+1-4 and ctrl+1-6 in photos view mode :)
And desert: All Photos keyboard shortcuts for Mojave
This is fixed in macOS 10.14.4 (Photo 4.0): spacebar now opens images and keyboard shortcuts work for editing.