What are some good messaging apps?

Hi, everyone What are some good messaging apps that don't ask for your phone number?
I have Facebook Messenger and Google Hangouts. I am looking for more apps that can message Groups. Thanks.

Forum: 

Skype

Skype is a good one but you already have it. So try Voxer. It's an app that you can create groups with and talk to them. As far as I know, there is no phone number required, I think it's optional.

kik is another one

Kik is another one that doesn't ask for your number.

They use usernames.

Unlike the other apps listed here, kik is text only.

Re: voice only messaging

Hi,
I'm still planning to try this app out. What type of app is it? Does it only allow you to call or does it have a chat feature?