Sounds & Projects management

Hello and welcome to the forums, These might be what your looking for.
Track templates
https://www.cakewalk.com/Documentation?product=SONAR%20X2&language=3&help=Arranging.08.html
Project templates
https://www.youtube.com/watch?v=obv6_xaQ8G8
 

You can either load one project at one time. By closing the project all plugins will be closed and unloaded.
Or you can "un-check Allow only one open project at a time"
Then you can load a few projects and switch between them.
But each project loads his own plugins and sounds - they will not shared.
For example: If you load 5 projects, each with NI Kontakt, then 5 instances of NI Kontakt will be loaded.
The sounds are software and the sounds (plugins) are loaded within the project and belong to a track - not a hardware, where you control and share your sounds outside the computer in a rack.

If you load two instruments into a single instance of Kontakt and those instruments share wave files, Kontakt will only load one copy of that data.   But this is a very narrow case.  Most professional instruments rarely reuse the same wave files (applies when the wave data is stored in a Kontakt .nkx file too) in more than one instrument.  You can get a win if you load the same instrument many times, but that is about it.  So if you need say multiple copies of the String Ensemble Violins, be sure and load them into a single Kontakt instance.
 

This was one of the reasons I suggested project and track templates.
I know my comment was kind of overlooked but its very much related.
Set up one project, save it as a template and open multiple projects using that same template.
A project template can also save data along with tracks (save midi/audio along with the template).
 
I don't know maybe im missing something. But it doesn't seem like it.
 

Chuck has the best answer. 
It's super easy to have one song with the instruments you want and all fine tunes and tweeked/ you save that as a track template, open the other songs and load it in,done.. this is something I do day in day out with my backing tracks. I want them to all play like a live band , not a different band for each song. 
 
The other option I also use a lot is each VST has custom pre sets you can NAME and  save. 
Once you have the instrument loaded you can save time looking for it again by saving it to the preset menu. 
Example in Session drummer and AD2 I use song names once I get a kit sounding right for that song. I then will know what style of music the kit will be for. 

Templates is working indeed in general, but for the flexibility I described, it is not appropriate.
My project has something like 15 to 20 Go of loaded sound, so the problem is about loading time (from one project to the other) more than presets itself.
 
Virtual midi could be a solution indeed,  I have to thing about it :)
Maybe two computer too, but it is another story...

francois_1
Templates is working indeed in general, but for the flexibility I described, it is not appropriate.
My project has something like 15 to 20 Go of loaded sound, so the problem is about loading time (from one project to the other) more than presets itself.
 
Virtual midi could be a solution indeed,  I have to thing about it :)
Maybe two computer too, but it is another story...

Project Templates are not about presets.
Its about loaded VST's and VST plug ins all ready to go at the drop of a dime.
If you open all these projects, there is no loading time.
 
You might need to explain yourself a bit clearer in order to receive the best possible solution.
For example: Why not put all these projects in the same project and export them in separate data files ?
Why the need for multiple open projects using the same exact plug ins, synths, exc.
And what is " "standard" sounds" ?