Are there any alternatives to the handshake worldwide?

In Japan, you bow. Handshaking is rare; bowing is many times a day.

Interestingly a lot of the stuff the world is doing now because of COVID was commonplace in Japan long before. In Japan, even before COVID, you wouldn't go out of your way to make physical contact with most other people - generally no hugging or handshaking, though exceptions existed. You bowed instead.

(As was referred to in the comments, sometimes physical contact was still pretty unavoidable, due to crowding, particularly when using public transportation.)

They were also already wearing masks part of the time, being extra careful to sanitize things with alcohol, that kind of thing.

In the Arabic world, for example Egypt, you can place your right hand on your heart and bow your head slightly.

In Arabic you can also say "Tasharafna" (it's nice to meet you).

The "hand on the heart" gesture conveys well meaning, even if the other person doesn't know this gesture from before.

It's also very practical in times of Corona, and much more polite than the "corona elbow" or "corona foot tap" gestures.

One of the most unique ways of greeting others that I have ever seen is the Sudanese way of greeting.

Each person will gently touch the other person's right shoulder using the right hand. A handshake usually follows this.

There is the Narmaskar or Namaste greeting in India: https://en.wikipedia.org/wiki/Namaste#:~:text=Namaste%20or%20namaskar%20is%20used,his%20or%20her%20generous%20kindness.

In the answer by @Franck Dernoncourt, the elbow bump has been mentioned.

It's very common, between friends, where I live**, since Covid19

I've even seen and used the "air bump"! The people making the greeting stand apart and move their elbows as though to touch without actually making contact.

** South of England