I believe this is the current Schengen list:
Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland
The 90 is in ANY 180 day period so keeping track of it can be difficult. When I spent a lot of time in Europe before I had residency, I used a Schengen calculator. There are a number of them on the internet. Someone once stated that one of the Nordic countries allowed 90 in 180 days beyond the Schengen limit, but I don’t remember which or know it to be correct.
Which means countries with land in Europe that are not in Schengen include:
Albania, Armenia*, Azerbaijan, Belarus, Bosnia & Herzegovina, Cyprus, Faroe Islands, Georgia, Ireland, Kazakhstan, Kosovo, Moldova, Montenegro, North Macedonia, Serbia, Turkey, UK, Ukraine.
I also don’t believe that Andorra, Monaco, San Marino and Vatican City are in Schengen, but you can not reach them without entering Schengen and there isn’t any passport control so you will end up having been in Schengen even if you were not.