There is no official list, but if you look for 'high fluoride toothpaste' in a search engine you will find some brands that offer a higher amount of fluoride. Most toothpaste contains 0.3% fluoride or less, which may be enough normally, but prescription strength toothpaste will usually be 1% or more (this is considered safe in most cases). You should also look to see if a toothpaste is recommended by the NHS (saying 'recommended by dentists' isn't as reliable).
However, the best way to find a really good toothpaste is to ask your dentist. It may not be necessary or even a good thing for everyone to use a high fluoride toothpaste - for one thing, it also depends on fluoridation levels in the water where you live. So you should definitely ask first. You can also get general information on fluoride here.