Note, too, that the materials are similar in their formality – and for formality, read roughness. Mariano’s linen jacket with his fresco trousers; my donegal-cashmere with flannels; Luca’s linen/silk jacket with gabardine: all have a similar-enough texture on bottom and top. The only exception, I find, is when the materials might be too similar to allow contrast. My Liverano jacket, for example, works best with smoother gabardine or worsted trousers.
See also post here with large selection of photos (only some of them of me…).
If you’re starting from scratch, keep it simple: just grey trousers, perhaps mid-grey flannels and pale-grey frescos; then any dark jacket that is obviously not part of a suit. Once you start looking around, you’ll find plenty of other combinations you’ll want to mimic.