In-game future content refers to things already in the game, but is showing a preview of content. Unlike future updates, the content exists in the game showing the update that is to come, this can be things such as new armour, effects, towns or locations. The updates may stay in game for possibly years before their actual release, such as the gnome update. Future content is normally previewed by members first, and later released in free to play. Jagex sometimes releases more of the content months before the update it released.
It started with a small hint of the Gorilla mask, and then later in May 2012, Mad May began with previews of graphically updated monkeys, monkey capes, monkey hats, monkeys in barrels; all hinting at a future graphical update to monkeys. In 2016 Dojo Mojo, the agility skilling pet was added, using new ninja monkey graphics.
The graphics of the GoblinSnotgut have been updated, while the other goblins' have not yet. Two months later, Kringle is released, with an entirely new sort of graphics. It is unknown which one will be used as the base. With the release of Carnillean Rising, Slimepits and Nostrillia (the first female updated goblin) use the definite new graphics.
Laidee Gnonock's chathead was the first updated gnome chathead, while the other gnomes got updated 2 years later, with the release of the new gnome quest, The Prisoner of Glouphrie.