If you only have TiltViewer galleries and don't intend to have anything else in your svManager installation then you can delete the plugins for the other gallery types. Each plugin lives in a subfolder of svmanager/plugins. Delete the folders named svmanager/plugins/autoviewer etc. Don't delete the tiltviewer plugin! Keep a backup in case you change your mind.
The drop-down list for new gallery types will still show in svManager but it will only contain TiltViewer.
If that approach feels a bit drastic then you can change a setting within each plugin that will hide it in the new gallery dropdown. I'll use AutoViewer as an example.
Edit the file svmanager/plugins/autoviewer/settings.php and find the following line:
Change this to:
Do the same for any other plugins that you want to hide.
SimpleViewer Support Team.