The SCP Foundation is purely fictional. It's a collection of imaginative and often creepy stories and characters that are made up for entertainment purposes and have no basis in reality.
A good way is to follow your interests. If you're interested in space exploration in science fiction, look for series like 'The Expanse'. It has books and a TV show. Start with the books to get a more in - depth understanding of the world and characters, and then watch the show to see how they've translated it. In fantasy, if you like medieval - like settings and magic, 'The Witcher' is a great option. There are books, games, and a TV show. Begin with the books, then move on to the other mediums to see how they all match together in terms of the story, characters, and the overall world - building.
Crossover fanfics also attract new fans. If someone is a fan of another franchise and then discovers an interesting SCP Foundation crossover, they might become interested in the SCP Foundation itself. This helps to grow the community. For instance, a 'Star Wars' and SCP crossover could draw in 'Star Wars' fans who are curious about how the two would mix.