Agree it's down to personal choice and circumstances, but this is what I wear most often so would be my essentials
Black skinnies - don't care what's in or out, they work with different types of boots, dress up or dress down. Blew my mind that M&S currently have great ones - they were recommended on here.
Mid blue or indigo boyfriend jeans - conversely I prefer blue jeans to be baggier
Wide leg palazzo trousers - my 'going out' ones are silk and from Grana a HK brand, day time I love linen ones from Seaside Tones.
Long maxi dress than can be thrown on but also always looks put together, mine favourite 'going-out one' is from Arket, my favourite during the day one is Whistle. I also have an insane one from Daughters of India, which I love and is perfect for the hot country I live in but which is so big its a bit of a pain in the arse.
Variety of long and short sleeve tshirts - long sleeves are wide jersey tops from hush, short are supersoft slash neck from boden
Silk shirts - I have the same in blue, black and cream also from Grana, but sized up
Shoes - Tiger Mexico 66 slip ons, sandals by Sam Edelman and funnily enough my most comfortable boots are a few years back by Boden.