Select a region to peruse the online catalogue.
Different regions have different online enabled titles, and not all are back online yet. Most USA/EURO titles will come back online together (if released in both regions) because the internet protocols between the continents was practically identical.
Japanese titles are taking a lot longer to get back online due to the way the early Japanese internet was connected to the Japanese phone system. While none of these titles are back online yet, there are some notable exclusives that include online multiplayer and extra features. Sega Rally Championship 2 includes online multiplayer, for example, whereas it doesn't in the Western releases.