The fact that Nintendo has plans for Animal Crossing: New Horizons, is, of course, no news to anyone, but thanks to data miner _Ninji, we now know a whole lot more about what the future carries. The data miner recently posted all findings to Twitter, and we have pasted them below for your convenience. Beware as it could be considered spoilers as it is technically not rumours - but actual information from the game code, should the mined data be legit.
• There's entries for two extra museum upgrades. All three levels (after the tent) seem to contain an art section.
• There also seems to be two standalone buildings: the museum shop, and the museum cafe (which incorporates a Gyroid section).
• Redd appears to have a ship which will dock on the 'secret beach' at the north of the island. That particular acre is called Nつねきち internally - つねきち is Redd's Japanese name. The 'fake art' mechanic is coming back, but I don't know more details.
• Bushes are coming back: azalea, hibiscus, holly, hydrangea, camellia, osmathus Those might change; the list actually changed between 1.0.0 and 1.1.4! Vegetables that you can grow and pick: tomato, wheat, sugar cane, potato, carrot, pumpkin.
• 1.0.0 has a file for a "Seafood" Critterpedia page that's supposed to contain 33 items; the only one actually in the released game is the manila clam.
• There's a 3rd Nook's Cranny referenced, but no details on features or upgrade requirements.
• Diving will allow you to obtain fish (a different set from fishing ofc) and seaweed. There's a portion of the save file reserved to store them already! (I'm not sure how, or if, this ties into the "Seafood" critterpedia page — not enough info yet).
• Unused shopping interfaces: 'cGardening', 'cMuseum' (museum shop?), 'cRealEstate', 'cGallery.' These might not be full-fledged shops. This particular system includes Nook Miles redemption, bridge/slope type purchases and Kicks's shoes, for example.
Thanks Destructoid