I'm wrapping a trip through Europe and I only packed black tshirts and a flannel button-up "for color".
Black is timeless, hides stains and sweat, easily layers of you want to buy something to add to it, matches multiple colors of trouser/jean/shoe.
I vow on my next trip to pack fewer jeans (2 pair vs. 4), more socks (4-6 thin pair vs 3), fewer overshirts (1 vs 3, maybe a second that is "classy").
I value having boots along with running shoes.
I'm a 2 bag traveller. Even with my bloated clothing budget, shoes and toiletries volume, I was able to fit it all in a 46L carry-on backpack + a normal backpack, with a satchel rolled up for use on daily walks.