The main thing about scientist attire is that it should be appropriate to their setting.
The good news is that when you mainly work in an office, as I do, you can dress pretty much as you like (as long as your clothes are still decent and office-appropriate)!
I have a collection of graphic tee-shirts that feature video game and film themes, most of my sweaters are probably from H&M. I also have loads of scarves because they can make any outfit look snazzier (and they’re great to deal with overzealous A/C). In the warmer months I prefer skirts – somehow I always end up getting skirts with similar checkered designs to the point where it’s a running joke that I can wear a different skirt every single day but it looks like I’m wearing the same one over and over again. In terms of shoes, depending on the season and on the weather, I’m either wearing rainboots or winter shoes or Converse shoes (light blue). Of course with rainboots and winter shoes, it’s important to also keep “indoor” shoes in the office to change into otherwise it would be unbearable.
When there are important meetings or I have to give a talk, I will usually dress up a bit. I have a few nice dresses but I draw the line at wearing heels – some people are good with heels, I have no problems walking in them but they’re just not as comfortable as flat shoes. I tend to stick to darker Vans, they look fancy enough without looking as casual as Converse shoes.