For issue branches: <issue-key>(optional-keyword), all lowercase, hyphen separated. eg...
abc-123abc-123-new-feature-nameThis matches the commit message convention of "<issue-key> plus short description".
Since we use Bitbucket and JIRA, pretty much wherever the JIRA key shows up it's a link back to the issue; and the issue links out to the pull request. Links things up nicely. Some teams actually create the branch from the JIRA page to ensure the key is correct.
Other than that we basically only have master and branches named according to the test server they deploy to.