This matrix, developed by the legal firm Fragomen, provides:
a) the current, Pre-Brexit rules that apply to UK nationals traveling to EU member states
b) whether each EU member state has proposed or implemented special no deal Brexit arrangements covering short-term entry for UK nationals
c) the current rules that apply to short-term travelers who are third-country nationals - presuming that these are the rules that will apply to UK nationals following a no deal Brexit.
The guidance covers immigration rules in Austria, Belgium, France, Germany, Italy, Malta, the Netherlands, Portugal, Sweden and Spain. You can use the dropdown box at the top of the second sheet to select the country you would like to view the rules for.
Download the file here.