Is there any limit on the members of queue in salesforce

Question

How many members/users we can add in a queue?

Answer 1

There is none other than the fact that you're limited to how many users/licenses you have in your org to include as members. This isn't specifically called out in the Queue documentation, but may inadvertently be in the Chatter one.

Considering added members to a Queue are stored in the same back-end object GroupMember, I think it's safe to say it's unlimited for Queues as well. You can quickly test and see by adding the public group "All Internal Users" to a queue and seeing no issues.

Important to note, that Queues also have the benefit of not having a limit to how many you can create which differentiates itself from the group limit above.