Acustica has released two free plugins

Acustica, the company that recently created Lava, the mic emulation program, has very generously released Fire the Pump, a free saturation plugin and Artic, a free program that is part compressor, part saturator, and part limiter. Both sound very good. You may or may not like their sound on Pianoteq, but they're very good on vocals and acoustic guitar, and I would imagine many other instruments. See https://www.acustica-audio.com/pages/acqua-manuals for the manuals. (You'll want one for Artic.)

You must install Aquarius, their download manager, to download these two programs: https://www.acustica-audio.com/pages/aquarius

Note: Acustica's programs often use a lot of processing and if you already using a lot of effects on a track,they can slow things down to a crawl. They work very well with Reaper, however.