VSTs are so great. I have a massive collection of free instruments and FX that I've tracked down. There are SOO many to choose from...
But I notice it every time I'm working on a new song. I always use the same VST FX. At times I use others as well, but these five FX are used in, literally, every song I make. Here they are and why I use them so much.
Classic Compressor / Chorus
I've grouped these together, so I could get an extra VST in this list :) . Every drum sample I use gets the Classic Compressor - usually the default preset. It adds punch and just really brings the drums to life. Some of my synths get this treatment also.
The Classic Chorus gets significantly les use - but for any sound I want to be 'three dimensional' the default preset on this FX is perfect.
EasyQ
Nearly every single track in every single song I do gets the EasyQ. My only criticism is you can't automate the nodes you create. This may be a limitation in the VST guts since they are dynamically added/removed. But still. I just love this EQ. It is lightweight, I have other parametric EQs that are such resource hogs they are nearly unusable.
Now that I'm writing this, I'm thinking it may be time to see what else is out there, it has been a while since I've tried out EQs.
ReaComp
The ReaComp compressor is shipped with Reaper and it handles sidechain compression. So that is what I use it for. There is typically a need for at least one instance of this in every song. I really should explore what the plugin is really capable of but so far it's just a sidechainer for me.
TriDirt
This little beast is amazing. It is 1/2 three band distortion pedal, 1/2 two band filter. And it sounds sick! The filter on it is one of my favorites and sounds really good when you automate it. Some of the filthiest neuro-bass I've ever made utilized automated TriDirt filtering. Each band can be set to one of - I believe 5 - types of distortion and the overall output is filtered by a treble and bass value.
Classic Delay
Like the other Classic FX the delay is just so solid. I've used other delay FX that are great. One of them does super analogue style feedback (If you set it to high it begins squealing, just like a meatspace delay pedal). but just like coffee when I've tried to switch to tea, I always come back to the Classic FX.