1) Nova is not only an EQ, but also a kind of multiband dynamics processor
2) Slick EQ is "just" an EQ for somewhat different purposes
There IS a completely free version named only "TDR Nova" which has a few
features/functions less than the "GE (=Gentleman´s Edition)", but is
still quite useful.
As I see, Nova GE has an additional "smart operations" feature, but you
might get close manually with the free version.
All TDR plug-ins have a free version and a paid GE/Mastering version
with more features and I suggest everybody to get at least their free
stuff - if you like, be nice and buy the GE and/or Mastering versions.
This is good stuff from a bunch of guys who won several "KVR Developer
Challenges" with their plug-ins, so you can assume they know, what
they´re doing.
Besides that, once in a while Izotope "Ozone Elements" (and more seldom
"Neutron Elements") is available as a free give-away - both include a
"smart"/"learn" feature, which analyses the incoming audio and provides
some suggested settings. Look out for give-aways of those in addition to
TDR Nova (GE), so you can try which works better in a given situation.
Good luck with your quest and enjoy "playing" around! ;-)
Phil