Beside the plug-ins mentioned above (from Waves, Arturia and Native-instruments), I am using a bunch of different plug-ins. Since I both use Cubase/Live and Reason, these different plug-ins are spread across two different technologies: "VST" for Cubase and Live, and "Rack Extension" for Reason. Most companies making VST-plugins also makes plug-ins for the formats AU,RTAS and AAX (used by iLogic and ProTools), however RE (Rack Extension) plug-ins are a complete different format and fewer companies are making plug-ins for Reason. Here below I have mentioned a few of the plugins I use (grouped by Company.
For a long time I had my eyes on Omnisphere (before that "Atmosphere"), but its hefty price-tag ($499) kept me from buying it. In both Atmosphere and the first version of Omnisphere you could only use the samples that came with the factory library. However this changed with the release of Omnisphere II, which except its huge factory library (+50 GB) also allows you to use your own waveforms as basis for its sounds. So in the end I could not resist any more, and I ended up purchasing Omnisphere II. Omnisphere is perfect for long evolving pads and soundscapes that are perfect when making sound-tracks for movies, and this is also how many perceive Omnisphere. However it can also be used to make all other kinds of synth-sounds (why not use a Omnisphere-patch for your Bass and Lead-sounds?). The +50 GB factory library contains +10.000 presets, but they added a nice browser that quickly lets you search the sound you want, and watching the videos they have made, you quickly learn how to make your own patches, whether you want to use the samples from the factory library, or if you want to use sounds from your own sample library.
Spectrasonics have other products in their portfolio (RME Stylus, Trillian and latest KeyScape). If you own any of these other products, their samples are also available within Omnisphere II. As of now I don't own any of these, nor do I plan to in the relative near feature. Like Omnisphere these are also in the expensive-end of the price-scale, so you really NEED them before you actually go buy them (at least on my budget).
I had my eyes on the product Alchemy (from Camel audio) for a long time, however I never got to purchase it (since Camel Audio ended up selling Alchemy to Apple, who discontinued it as a stand-alone product, and today it is only available for Mac users as a plug-in in Logic). If I was allowed only to own/use a single softsynth, then UVI Falcon would be my choice. In many ways you can compare it to Omnisphere (even though I many times prefer Omnisphere when making "long evolving pads and soundscapes"). Falcon is a lot more versatile than Omnisphere in the way it features a lot of different synth engines, both based around more traditional oscillators and samples (the Omnishpere II library do however contain a lot of waveform samples from diffent hardware synthesizer). The many differnt "synth engines" in Falcon more or less lets you accomplish what you could do in Alchemy, so I can only be happy I never got Alchemy (considering the way things went), and I in stead "waited for" Falcon.
UVI also produces Sound Libraries or as they call them "soundware". These libraries can be purchased even if you don't own Falcon (in which case you need there free "player" called "Workstation"). However if you do own Falcon you can bring these "instruments" into Falcon, where you are able to do much more to the sounds as you can do in Workstation. Basically most of these soundwares are "sample libraries" (they are not all "virtual instruments" emulating real hardware synthesizers). I went for their "Vintage Vault" bundle containg a lot of sample from a lot of different classic hardware synthesizer (so along with the V-collection from Arturia I now feel fully covered in this segment of the sound-palette).
Working with audio you cannot avoid hearing about the company iZotope. iZotope are perhaps best known for the mastering tool Ozone and their sound-restoration tool Rx, however unfortunately I don't own any of these (in stead I have invested into Waves plug-ins). However I have iZotope's spectral synth Iris2 along with the free plug-ins Vinyl
(DDLY costs $49.00, however was offered for free for a short while, when being released).
Iris2 is "a special kind" of synthesizer that accepts samples as input. It comes with its own +10 GB library, but you can bring in your own audio-files as well. I really like that Iris's library consist of "normal" wav-files, so you are able to use these audio-files in other synths/samplers as well (both the libraries for Omnisphere and UVI comes in their own special format, hence they cannot be used in other products). What makes Iris special is not the fact it can use audio in stead of oscillators (many synths can do this), however Iris has a special take on how these audio-files are used. Beside using traditional Filters (Envelopes, LFOs and effects) you are able to "draw-in" your own filtering. When "drawing" these filters the X-axis represent time, and the Y-axis represents frequency. A patch can consist of 4 different sounds (wav-files). So perhaps you only want to use the low-frequency sounds of Audio-1, the mid-frequency sounds of Audio-2, the high-frequency sounds of Audio-3 only in the beginning of the sound and Audio-4 will come in and out during the time it takes to play the sound, some time adding to the low-frequency sounds and sometimes added to the high-frequency sounds. This lets you merge 4 very different sounds (I would otherwise think you could not combine), and the "sum of these" will have the listener unaware how the patch was made.
When iZotope introduced Neutron they offered their "Music Production Bundle2" for at reduced prices, hence I was able to pick it up for $299 (or $373.75 including taxes), but considdering the normal price was $699 (excl. taxes) it was still a good price. This bundle includes: Neutron Advanced, Ozone 7 Advanced, Nectar 2 production suite, VocalSynth, Trash2 Expanded, RX Plug-in Pack, Insight.
My first encounter with McDSP was in Reason where I got their (RE version) of FutzBox and their bundles of Equalizers and Compressors. I loved to use these products in Reason, so when I started using Ableton Live and Cubase again, I was missing out on these. In the summer of 2016 McDSP offered many of their products on a discount, so I ended going for their 6050 ultimate channel strip (contained all of the EQs and Compressors that I loved from Reason, beside many more additional Compressors, EQs and distortion devices) along with a VST edition of FutzBox. When SA-2 Dialog Processor was on sale september 2016, I got that as well.