Files with otg file extension can be generally found as drawing templates in OpenDocument Format. Used in OpenOffice.org and other Oasis based office suites.
Software that open otg file
OTG file extension - OpenOffice.org graphics document template
What is otg file? How to open otg files?
The otg file extension is mainly related to a graphic template used in OpenOffice.org and similar suites based on Oasis platform.
The OpenDocument Format (ODF) is an open XML-based document file format for office applications to be used for documents containing text, spreadsheets, charts, and graphical elements.
The file format makes transformations to other formats simple by leveraging and reusing existing standards wherever possible. As an open standard under the stewardship of OASIS, OpenDocument also creates the possibility for new types of applications and solutions to be developed other than traditional office productivity applications.
MIME types:
application/vnd.oasis.opendocument.graphics-template
The default software associated to open otg file:
Apache OpenOffice Draw (OpenOffice.org Draw) 
Company or developer:
OpenOffice.org Project Team
Apache OpenOffice Draw (OpenOffice.org Draw) is a fully-featured graphic editor that allows users to draw quick sketches or complex diagrams. It is easy to use and has many nice features. Draw comes as part of OpenOffice.org productivity suite.
Company or developer:
The Document Foundation
LibreOffice Draw is a useful software tool for creating various drawings, diagrams and other simple graphics. It's an open source program that comes as an integral part of LibreOffice suite.
Apache OpenOffice (OpenOffice.org)
Company or developer:
OpenOffice.org Project Team
Apache OpenOffice (OpenOffice.org) is popular free office suite for variety of operating systems. OpenOffice.org is compatible with other major office suites. OpenOffice.org can create and edit documents (Writer), spreadsheets (Calc), presentations (Impress), graphics (Draw) and databases (Base). OpenOffice.org is localized in to 120 languages.
Company or developer:
The Document Foundation
LibreOffice is a comprehensive, professional-quality productivity office suite that is completely free to download. It includes word processor, spreadsheet, presentation, database and drawing software and is available in more than 30 languages and for all major operating systems, including Microsoft Windows, Mac and Linux (Debian, Ubuntu, Fedora, Mandriva, Suse, ...).
List of software applications associated to the .otg file extension
Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open otg file, edit otg file, convert otg file, view otg file, play otg file etc. (if exist software for corresponding action in File-Extensions.org's database).
Hint:
Click on the tab below to simply browse between the application actions, to quickly get a list of recommended software, which is able to perform the specified software action, such as opening, editing or converting otg files.
Software that open otg file - OpenOffice.org graphics document template
Programs supporting the exension otg on the main platforms Windows, Mac, Linux or mobile. Click on the link to get more information about listed programs for open otg file action.
Microsoft Windows:
Apple macOS / Mac OS X:
Multiplatform:
Main software associated with otg file by default:
Apache OpenOffice Draw (OpenOffice.org Draw)
LibreOffice Draw
Apache OpenOffice (OpenOffice.org)
