How can I get a list of remote repositories from gitolite?

For single repo which name I already know I can use this command:

git clone gitolite3@remoteserver:repo.git

But how can I get list of all repositories on remoteserver available for cloning?

Try ssh gitolite3@remoteserver. You'll get a list of all repositories available. To be clear, this will not get you a remote shell on the server. It only displays the available repositories.

This works if you have gitolite installed, which I assume you do, given the username.

Keep in mind that this only shows you which repositories your user has access to, as well as whether you have read/write permissions for each repository. Repositories that gitolite3 does not have permission to read or write will not appear in the output with the above command.