I'd also like to add (and echo @Tobias recommendation of TH3) that you shouldn't underestimate a lot of CbB's built in effects. The Sonitus suite, for example, looks pretty old and useless, but it's far from that. I do a lot of pretty big productions and that suite of effects is my go-to for almost every project. Light on the CPU, transparent sound and they just work. Adding to that you have all of the great ProChannel modules too. The EQ has great character, you have the console emulation which, when you strap it over a lot of tracks, gives great character, and the tape simulator is great for warming things up and knocking the peaks off of stuff that's too "digital" sounding.
I think with the exception of a couple of good mastering effects, you can easily do world class mix/masters with no additional effects needed other than what comes with CbB. If you're just mixing, you easily have enough stock stuff to get the job done well.
That said... who can say no to more free stuff? ?