Three-finger dragging on laptops with touchpads: https://support.apple.com/en-us/HT204609 It says it's for dragging windows, but it works for all dragging, including files in Finder etc. Couldn't do without it now.
Increase Contrast, which I prefer not just for aesthetic reasons (it gives a slightly old-school feel to the interface), but because it delineates areas of windows / apps more clearly: Preferences > Accessibility > Display > Increase Contrast. This will automatically turn on Reduce Transparency, but I used that setting anyway, to reduce distracting detail.
You can also get this behavior with “double tap to grab”, which allows you to pick up your finger and put it back down repeatedly as you are dragging something around. Same idea, different (turned-off by default) gesture.
Increase Contrast, which I prefer not just for aesthetic reasons (it gives a slightly old-school feel to the interface), but because it delineates areas of windows / apps more clearly: Preferences > Accessibility > Display > Increase Contrast. This will automatically turn on Reduce Transparency, but I used that setting anyway, to reduce distracting detail.