I agree with u/merseykat that if you're going into the true 'luxury' category of bedding you won't want to wash them on hot and that warm wash will be the max you'll want to wash such sheets at (delicate cycle/dry, essentially). If your clients also do not want flax and wish for 'crisp' sheets that don't require much ironing then linen will pretty much be out of the question as linen wrinkles as a feature (and all linen is made from flax), and while percale cotton needs ironing far more than cotton sateen, percale cotton is what most hotels use for their 'crisp/smooth' texture that most know. Sateen cotton is more 'silky-soft' and is usually the crowd favorite of most people in the world, I would say (especially higher thread-count sateen). Embroidery is nice to look at, but as someone with sensitive skin I cannot abide sleeping with lace trims or anything that rubs against my skin even the slightest bit when I sleep, so if your clients are looking for sheets that are going to be used then I would not recommend fancy-looking sheets unless they want to use them for decoration-only, you know? Most brands that are considered luxury are ones like Sferra, Frette, Amalia Home, Pratesi, St Geneve, Matouk, Letto, etc. and I would highly recommend getting as many swatch samples (or visiting a local linen shop that has the samples in-store) before making any purchases. Usually 'the best' cotton fabrics (imo) are Giza or Sea Island cottons (extra-long staple length) in either percale cotton (more crisp and smooth), sateen cotton (warmer but very soft) or a cotton/silk mix (usually the most expensive but most fussy). You could also go full silk but that sometimes is not the best as it can more easily wear down and has to be babied when washed (always cold wash, special detergent and usually low/air dry). If allergies are an issue/skin sensitivities then the best fabrics to use are either full-silk (Castello Home or Amalia Home has some silk options that look quite nice) or bamboo as they work best in those situations, though for bamboo it's a bit more challenging to find a really higher-end version (like SDH Legna, which is a crowd-pleaser for many), but again, both will need to be washed with cold/warm wash. As for duvet inserts/pillows, most really adore (for luxury homes) Eiderdown pillows/duvet inserts and they will definitely break the bank if you go that route, otherwise brands like Frette will have some really nice options for goose down if they want the 'light and fluffy' look in their beds (but will have to have a colder room temp to be able to sleep under very comfortably if their humidity levels where they live is semi-high). If allergies are an issue, though, wool or silk tend to work well for allergy suffers and are hypoallergenic (but cannot be washed), so keep that in mind, too. Hope this helps and good luck :) P.S. If you go with high-end luxury bedding, especially for sheets, you won't be looking at many options with color, especially really nice Giza cottons from brands like Frette, etc. Most color options tend to be only via special order companies, so if your client is looking for Giza cotton sheets that are Fuchsia then chances are they'll have to special order that and there's a possibility that the quality of the sheets might be degraded by the dying process. More on reddit.com

Don't get linen sheets. You'll be spoiled forever, there's no going back! More on reddit.com

Can I be so honest I love target bedding lol. It's not natural fibers but it is affordable and so comfy and holds up! Literally have had my sheets forever, tried fancy ones and they got a hole in them in 6 months. One day I'll be fancy and get quality sustainable bedding but today is not that day haha. More on reddit.com

The Company Store. Hands down the best Quality. Watch for their sales. More on reddit.com