None of us here are really discussing Sonar. It's just been mentioned a few times, so the thread probably should be moved. Anyway please carry on don't want to hijack the thread with talking about how it should be managed. Otherwise might be moving it to forum discussion forum :)

The reason I posted here is that I was looking for plugins to COMPLIMENT the stock X3 plugins so wanted to "target" X3 users
 
However, due to the development of the thread I agree the software forum is probably now a better fit
 
 

ok,  I tried to keep it X3 related by suggesting the OP tried out more of the bundled stuff and the additional PC plugs,  but to save further argument, it's being moved.

Boydie
The reason I posted here is that I was looking for plugins to COMPLIMENT the stock X3 plugins so wanted to "target" X3 users

makes sense

Boydie 
However, due to the development of the thread I agree the software forum is probably now a better fit

i don't understand how you or anyone could have expected anything else? without the sonar context the question is nonsensical

Boydie
...I was looking for plugins to COMPLIMENT the stock X3 plugins...

With that specific focus in mind, what you want to be looking at are things that aren't already bundled with SONAR -- NOT things that may or may not do the same stuff better. Fortunately, you really do already have - literally - everything you need in X3. Not just blowin' smoke; you really do.
 
That wasn't always the case. For a long time SONAR didn't have an opto-style compressor or a good auto-release limiter and everybody had to go third-party. Today, though, every basic category is covered. Not just adequately, but well-covered and perfectly capable of making professional-quality records. 
 
So what's X3 still missing? I can think of only two things: a dynamic equalizer and a really good harmonic exciter. The best of the dynamic EQ category would be either MDynamicEQ or MAutoDynamicEQ from Meldaproduction. Both have been on sale multiple times this year. For harmonic exciter, SDRR from Klanghelm is good and cheap. But if you go with Ozone, it includes an excellent exciter, negating the need to buy another one.
 
Third-party mastering tools remain popular, but mostly for ease-of-use - not because they're drastically "better". Ozone would top the list of plugins that don't do anything new but are just easier to get good results with. But it's largely a matter of personal taste. Ask for recommendations and you'll get as many opinions as there are users for each of the popular products. Truth is, all of them do just fine. But Ozone is far and away the easiest to use.
 

i use very few plugins,
some are freebies i've collected as i find particularly good ones (such as SPAN)
 
but
 
i use the WAVES plugins the most.
 
my go-to plugs:
L1 (mixing)
Renaissance comp (mixing)
Renaissance Channel (mixing)
C1 Compressor (mixing)
Deesser (mixing)
Renaissance Reverb (mixing)
SuperTap (mixing)
 
L2 (mastering)
LPMBC (mastering)
Linear Phase EQ (mastering)


 
i can do everything i need to do, with just those plugs.
 
 
 
but i also use the Sonitus Plugs (i'm still on Sonar 6 PE)
 
i use the EQ on almost every track, and i like the delay mono compressor

Ozone & Waves +1 ...consolidated interface. Ozone starts you out with some workable presets, but you'll want to adjust them to your mix for optimum sound. Izotope offers a free online publication to cover the basics of mixing a master and some of their ideas on mixing approaches.
 
Honestly in a few cases I have used The basic plug-ins in Sonar X-3 and have gotten the same or better results as I did using Ozone. Don't forget that Sonar X-3 has pre built effects plug in chains for both channel and master work. So I don't necessarily always use Ozone, but if I were to steer you to something that can be an additional help that would be it. 
 
Some Waves plug-in are better than others. They tend to have a high level of quality though overall. I think you can download a free demo to try their stuff out. Good luck!

Now that this is moved I will throw a bit of a somewhat controversial option your way. You already have a lot of tools between Sonar and Komplete. Won't argue with suggestions to get Ozone or Waves. One thing I would throw in is perhaps pick up Fl studio if your focus is on top 40. Many top 40 songs now are put together using primarily presets from the synths included in FL. Granted they are all mastered in other software, but cranking out material like Iggy Azzelia's "Fancy" or Katy Perry's Dark Horse in FL is laughably easy in FL compared to most software.

When it comes to plugins, the best choices come down to personal preference.  Sound quality differs, but these days you can achieve good sonic results from just about anything if you work with it enough.  So, other factors like ease of use, stability, CPU usage, support policies, and price are more relevant factors.  And these likely will differ from user to user, so demoing the tools that interest you on your system with your material is a must!
 
The real benefit to third-party tools comes in when something about them clicks with your personal tastes and workflow.  If you really enjoy using a particular tool, you're likely to get your money's worth out of it, since you aren't struggling with poor GUIs or glitches and can focus on more creative matters. 
 
Now, there are cases where you want something specific and can't really achieve it with stock plugins.  Say, a lush Lexicon reverb sound or an authentic 1176 smack on your snare drum.  Third parties to the rescue in these cases, but again, it won't matter much unless you know how to use the tools. 
 
For me, the bottom line is that if a tool comes along that clearly improves on my existing stuff in some way, and it's priced fairly, then it's a good purchase.  Plugin technology is constantly improving, and is a fascinating industry.  Lots of fun to watch the market and play with new toys ... and sometimes buy them.   
 
Oh, and Ozone / Alloy are fine, but iZotope plugs aren't known for being CPU-friendly, so a demo is important to see if they'll actually be usable for you.  The Waves Gold bundle is also very comprehensive and a good value when on sale.  The ToneBoosters line is probably the best bang-for-buck suite on the market.  Higher-end tools from the likes of FabFilter, UA, and HOFA are worth looking into if your budget can take it.  Anyway, good luck and have fun! 
 
Cheers,
Eddie
 

Boydie

I am in a fortunate position where I can buy some plugins at the moment and Waves, Ozone etc. are names that keep cropping up in videos I am watching

I am just starting to research what is "out there" and wondered what other people are using

If everyone says - "xyz is a must have and I use it on all my projects because..." I can check it out

I'll put it simply. iZotope Ozone is well-known for enabling you to put some finishing touches on the overall mix.

For your question I encourage you to check out iZotope's Alloy 2. I put it on a heck of a lot of tracks. It's just one plug-in, loaded with lots of intuitive features and an excellent selection of presets. The presets alone can help you get close to what you want fast.

If you're looking for a bang for the budget, I believe iZotope offers a bundle (that's what I purchased) where you get Ozone, Alloy 2 and Nectar 2 all in one bundle. They are all excellent and might be close to the one stop shop you're aiming for. To top it off, they have consistent interfaces and settings so it is easy to use the all quickly.

There are Groove3 tutorials for each. You could get the Alloy 2 tutorial for a low cost, see how it works from that tutorial (and hear it in action) and learn it at the same time for next to nothing. Before making a decision.