Fortnite players will not need a Nintendo Switch Online subscription to play the game online with the Nintendo Switch. There is no information about other online games that do not require a subscription.
When asked “Can I play Nintendo Switch games online without subscribing to the service”, Nintendo replied that this was the case with “some games like Fortnite”. What other games fall under the exceptions and what criteria they have to meet is not yet known. In the same reply, Nintendo states that no Nintendo Switch Online subscription is required for eShop, registration of friends, sharing of screenshots on social media, software and system updates and news.
Nintendo Switch Online will be available from 18 September. A subscription costs €3.99 per month or €19.99 per year. The service is necessary to play online, as with Splatoon 2 and ARMS. Subscribers get access to the online store. According to Eurogamer, not every game will support this feature. Pokémon: Let’s Go Eevee/Pikachu is one of these games. One of the reasons is that players can exchange items online again via their stored files.
In addition to the ability to play online and save online, subscribers will also have access to a collection of twenty old games, including the original Donkey Kong and Super Mario Bros.