From Cardiff to Cologne in five hours and 35 minutes! Map reveals new route of £1bn cross-Channel high-speed rail service that will get passengers from London to France, Germany and Switzerland in
Overview maps of long-distance rail in Europe
Fantasy Eurostar map with services that can be started within a decade without any infrastructure work (more info in comments) : r/TransitDiagrams
Routemap | Eurostar
Eurostar.com: Book Europe Train Tickets and Holidays