There are currently two services (mercurial & paste) that do not appear in the navbar as far as I can tell. There are two open tickets relating to visibility of Mercurial in the navbar (#186, #212), but as sr.ht grows, the proposed solution of an option to switch between git and hg seems short-sighted.
It may be more effective to make the navbar items completely customizable so that items can be added, removed, and reordered by the user. This would allow people to have only git, only mercurial, both, or neither (if they wanted, for whatever reason). This would also be useful to help keep the navbar from getting cluttered as more services are added. Even now, I have a userscript set to remove dispatch and builds from the navbar as I have no need for either service.