While shaking hands is a common greeting, deal-sealer or sign of amity in many parts of the world, it's also a great way to transmit germs. (See: Final scene of Contagion.) Some have been making do with fist- and elbow-bumps, but given the current stress on social distancing I think no-contact is better. Here are some recommended alternatives:
As seen in this Japanese diagram, you can go 15 degrees for cazh, or crank the respect level up to full 45.
Make a gesture that says you are conjuring up friendship.
You have to be careful with this one, because it provides the opportunity for the other person to "neg" you. If you greet someone with a thumbs-up and they give you a thumbs-down, well, now it's awkward.
The Hulk Hogan
Sure it's a little confrontational, but definitely indicates that you are acknowledging the other person.
The Isaac the Bartender
Undoubtedly the best option out of all of them; it's cool, retro, and makes you and everyone around you feel like a million bucks.
Unfortunately, some jerk cut together a video that's FAKE NEWS because it suggests that the gesture can cause hurricanes. (It doesn't, or else me and everyone around me would be dead.)