I have a few of brands I like, mostly Australian.
Kookai is a flashy upmarket fashion brand that also happens to do solid good quality merino tops and dresses - mostly of the cropped/skintight/low scoop neck sort, but there are exceptions worth looking for. My favourites have all been found on ebay for between $12 and $30 with postage, so they end up pretty affordable. The best ones are long sleeved crew neck dresses or tops that are a double layer of fabric. I've been living in mine since moving back south to Victoria. Dresses for out in town, tunic and roll neck tops for weeding in. I'm looking at the sleeveless dresses for wearing to bed.
Ktena knitting mills does Merino Skins thermal underwear - my original pair is still warm and soft, a few holes and I replaced the waist elastic, but they're 6ish years old and were worn most days for most of the year for 4 of those. They're around $50.
Smitten (Australian, in Tasmania) does high end merino, dresses, tops, thermals, lots of lovely stuff, $100 and up retail, occasionally comes up secondhand. So far good quality, though I think the Kookai fabric is softer.
Also worth checking on ebay, Country Road does nice long merino cardigans that make a fantastic dressing gown. Light and warm, mine was a bargain at $25 posted. Also lovely with a dress in town on chilly days.
Other fashion brands I've tried - Witchery does lightweight merino, more delicate. Metalicus is thin, wouldn't buy again. My Scope brand top is thick, a little prickly but warm and comfy. David Lawrence was ok but wouldn't bother again.
I machine wash all of my clothes with wool detergent and sometimes on the wool wash - I do have a front loader though, not sure I'd do that in a top loader.
Hubby is fond of his Icebreaker (New Zealand) top, he's had it 15+ years and it's still very warm, with only a few small holes. I don't mind the brand but it's not warm enough for the price for me, even secondhand. Okay as a light weight mid season layer.