If you do not want to buy a garter belt too: stay-up bands or attached garters. A silicone lined top holds on its own and an attached suspender comes with its own straps. Anything else in the category needs a belt you do not have yet.
On sheerness: check the denier before the color. Under 20 is see-through, 40 to 60 is opaque, and the number tells you more about how a pair will look on than a photograph does.
If they slide down on you: wider band, not bigger size. A narrow silicone strip fails on a fuller thigh no matter what size you order. Width of the grip is the fix, and it is visible in the product photos.
If you want them to last more than a night: fishnet or fence net. Open weave takes rough handling, heels and fingernails. Fine sheer is beautiful and will forgive you exactly once.
If the legs are the outfit: rhinestone or patterned. Set stones and prints read from across a room, where a plain sheer reads as skin. That is the right call on camera and an overstatement in daylight.
On care: hand wash cool and dry them flat. A machine will catch a toe in the drum and that is the end of the pair. See all legwear for the rest of the range.