I'm only getting back into DAW music making again, but back in the early 2000's I used to lean heavily on Sascha Eversmeier's free plugins (http://www.digitalfishphones.com/main.php?item=2&subItem=1). He now works for U-He, but check out his Endorphin mastering compressor plugin which is very nice with lots of control. Obviously only 32 bit, but still sparkles a mix. My personal favourite is still his Dominion Signal Modelling plugin. Perfect for analogue tube/tape modelling.