iMessages has some cool new features and list is massive. I like the new bubble effects but couldn't find it. So I discovered after researching that when you tap on the SEND button you simply hold it down and the bubble effects (balloons, lasers, confetti, fireworks, shooting star) show up to choose from.
You may find that certain new features are not working so we suggest you read this page from AppleToolBox, where I found how to find the fireworks! Or you can watch this full review by zollotech of iMessages' new features below:
Or this ad from Apple shows the new balloon effect:
