The exceptions, which are now in place, are listed on the official homepage of the EU-Page. One expception is for employers which "are important for the post-corona recovery".
If the EU continues to ban travel from countries, which haven't COVID-19 under control, there could be some problems for riders from the continent America.
there are exceptions for people with a long term visa as well, so I guess they should be allowed to enter the EU. A two-week quarantine is likely to be mandatory for most of them though, I guess.