I've searched online, and found freely available additional templates for LibreOffice Impress at https://dohliam.github.io/libreoffice-impress-templates/, but superuser.se has nothing matching a search for "import libreoffice impress templates", and I haven't found the right button, apparently, in the LibreOffice GUI.
Given that I have a zipfile of additional templates, how can/should I import them to Impress?
Thanks,
Best Answer
While in LibreOffice Impress do the following
4. Navigate to where you have your templates stored and choose one of the
.otp
template files5. Click Open and you're done
Edit: this was done on LibreOffice version 5.3.5.2 on openSUSE Leap 42.3.