EFC, OMG, just google counter stools and you will find enough sites online that you can browse from now till next Tuesday! You can even use the store's own search function to specify height, back, arm, look, materials..... During my last remodel I ordered a counter stool from Winnipeg, Manitoba, CA and footstools from Miami, FLA, USA on the same day. I had fun checking to see each day on the shipping company trackers where which item was, en-route. I believe Winnipeg won. It was like my own little parimutuel betting parlor.

It's a STANDARD. Bar height stools have a seat height of 30" 99.9 percent of the time. Counter height is 24 ......99.9 percent : )

Hello Beatrice- The 42" countertop height is actually pretty standard for a wet bar or pub table area and there is a huge selection of bar stools that have a seat height 9"-11" below the counter height. This is the space for your knees to comfortably clear the counter and ideal placement for ergonomics of eating, etc. That seat height measurement is 31"-33". So when shopping, really pay attention to this more than the overall height which is dependent on backless and all manner of decorative backs. Here are some examples of bar stools that are black, not completely upholsted and have a seat height between 31"-33".

https://www.gardner-white.com/product/174032-shelby-barstool-black