It is my honest opinion that nail art is not worth the hassle. I offer glitter acrylics (but at £5 a set more, they are not popular) and the odd acrylic 3d flower (at £1 each they usually only have one on each hand and that's for a special occasion lol) but that's it really. (Where's the tight-arse smiley??)
Over the years I have dabbled with striping tape, foils, striper pens, stickers etc, and what I find happens is this: the client will umm and arr about whether or not to have any nail art, then when you've finished their infill/new set, they spend 10 minutes perusing designs, another 5 minutes discussing how you would adapt any display designs to suit their nail (or purse), then you have to sit and wait for their polish to dry sufficiently for you to start on them (at least another 5 minutes), then while you're doing it they change their mind :grr:
So after an extra half an hour or so of farting about, you end up with another fiver or whatever and you've probably made your next client late cos they faffed for so long. Or if you did book them sufficient faffing about time, you can bet your life that will be the one time they decide that a pink rhinestone on the ring finger is enough this time, and you will be sitting there for twenty five minutes twiddling your thumbs where you could have been at least half way through your next client's infills.
Sorry to be so negative, this has been my honest experience of nail art but I hope you have more luck :hug:
Edit to add: I have used Nailtopia stickers which are similar but have found that the top coat often yellows over the top of the more raised ones