mac or pc?
for a little warmth i personally recommend (mac only though) airwindows "channel"
Airwindows Audio Unit Plugins ...you can select between SSL, Neve and API emulation settings with dry/wet fader. it will add a little low end for sure. best thing: it's even free! (among many others)
i also love "drive" used very gently for busses or possibly even for master out (maybe 25% drive) and with a 50/50 dry/wet setting.
these are not compressing but can help warming.
