Instruments which have a non-discrete set of pitches (as well as voices) will tend towards the more harmonious (so to speak) tuning when playing in harmony. You’ll notice this in choirs, for example, where singing a capella, the chords will follow nice integral ratios of frequencies. Fretless string instruments and the trombone are obvious cases of instruments which can do micro-tuning, but it’s worth noting that brass instruments have finger loops on some of the valve loops to allow adjustment of pitch. Micro-tuning of the pitch can also be managed in wind instruments through adjustment of the embouchure so while woodwinds seem like they would be only capable of discrete pitches, there is some ability to adjust the pitch during performance.

On a church gig in the 90s, I encountered an organ which was not tuned in equal temperament so that playing guitar with the organ always sounded out of tune (something I only discovered once Mass began since we had rehearsed with a piano) and I had to switch to bass to be able to play an accompaniment that sounded decent.