The next big update for Stardew Valley will be the free 1.4 Update which will add a variety of new things as well as fix lingering bugs and increase the general quality of life of the game.
There is more end-game stuff like that to keep things going a little further after you’ve completed everything. I don’t want to spoil very much, so you’ll just have to wait and see for yourself!
Update 1.4 is coming to PC on November 26.
My goal is for the update to release on consoles & mobile simultaneously a few weeks after PC. Once 1.4 has a little more testing on these platforms, I hope to give a solid release date for them.