There’s a long list of things I like. Plugins are to a degree more useful when they do things in a way you like, sometimes constraining what you can do with them so as to keep things simple.
I’m going to start with what I used to use. I used McDSP’s Filterbank and Compressor bank for years and years, and then one year I didn’t pay to upgrade and just stopped using them. Very useful and easy, but at least back then they were maybe products of their time sonically. Had many of the failings of the plugs of that time (1997-2005). Might be better now, because everything is.
I have the Slate bundle but don’t use it so much anymore. The IR reverb is good, and the Eiosis EQ is one of my favorites still - but I feel like their meat and potatoes, the MixRack stuff, has a sound that’s not always right for things and can get a little fatiguing. Which is a pity - I do like elements of it a lot. The Neve and custom Slate eq’s are fun and Revival is often useful, and the “distressor” is pretty cool, and some of the circuit emulation is cool - but ultimately I wind up using it less and less. The tape simulator is fun too, but often does a little too much. The buss comps are decent but I just don’t reach for them so often. The Eiosis De-esser is very good.
What I use more and more of is the Kush/Sly-Fi bundle. The Novatron compressor is great - and I sometimes just use it for saturation (like SuperCharger:D).The Hammer DSP eq is just lovely. It’s general - it has three bands and no Q adjustment - but it’s hard to make it sound bad. The Deflector compressor is like a distressor in many positive respects. And the Electra EQ - I have a hardware one as well - it’s also hard to make a bad sound with it. The AR-1 is quite nice as a compressor.
From Plug-in Alliance, I love the bx_digital eq. Great all around and M/S too. DynEQ is also cool. I like the bx-limiter but only for the saturation. MPressor isn’t killing me. The Shadow Hills compressor they sell is terrific but I don’t own it yet.
Arturia’s series of compressors and eq’s is pretty good. I’m beginning to mess with Kilohearts’ stuff - it’s fun.
Altiverb is great. I only use a few things in it but they all make the world a better place. Otherwise for reverbs it’s the Abbey Road Plates, Kush Goldplate, the Slate reverb, EW Spaces, LiquidSonics and a newer IR reverb Avid are distributing - Convology - and a few algorithmic ones like Virtual Soundstage (which makes the VSL, SampleModeling and AudioModeling stuff much more unified-sounding) and Revibe II. Heard the Valhalla stuff, liked it, but I have too many more things to buy at the moment.
I’ve picked up lots of Waves things as they’ve gone on sale. All of the Abbey Road and TG things are fun. And I like a lot of the NI things for their utility - their 224 clone is very usable, SuperCharger is great, Transient Master is good - most of their stuff is at least serviceable. Guitar Rig works when many other things don’t.
The funny thing is, I tend to use broad strokes when working with orchestra. I like to make things work as they are and then make them a little better. I’ve read about folks who use transient designers on SampleModeling things to make them “better”, but I’m just not going there. I think of every layer of DSP as another potentially lossy version of the original. Eq, sure, gently. Compression, as needed. Saturation, whenever possible. But too many layers add too much latency and a lack of responsiveness - and as a real-time mixer that doesn’t work for me. I have some UAD things because I used to have a Quad card - but those are mixing tools, and you can’t use them for what you are listening to in real-time - can’t slap a Massive Passive plug-in on a stereo bus that you also play through. I do have a hardware one, that has only conversion latency from the interface - but no recall, so I use it less than I should.
When it’s drums bass guitar synths, anything goes. I usually mix virtual drums inside Superior 3 - I have the Slate drums too but their mixer is, shall we say, underpowered as far as processing - but the drums are already “produced”-sounding, so sometimes they are fine. I have a few Ampeg-type bass amp sims for Abyss, but Trilian usually just takes a little compression and maybe a hair of eq.
A few Orange Tree guitar libraries and the new Indiginus Steel get a little amping from Scuffham or Duitar Rig or Amplitube or Overloud THU. The SoundToys stuff is great - DevilLoc Deluxe is a treasure. Sonible SmartEQ2 is good for quick results with vocals. And OhmForce’s venerable Ohmicide is killer.
+1 for Trackspacer.
With some very rare exceptions, every kick you hear on any of my tracks is Sonic Academy’s Kick 2. Then about 75% of them have BoD dropped on the kick channel for fine-tuning.
me is the iLok story, so McDSP and Slate would be nice 
Either that or the old rule “the Internet is where people go to complain” is in effect, and although we have heard many complaints it gives the illusion that a vast majority have problems with it. 