In the building in the commons where you can visit other player's houses, I know the sun palace and the Sultan's palace have a npc that give gold daily but what I wanna know is are there any other houses or castles that have an npc that give gold daily?
Not a house/castle but can be placed in one, the Shinobi Dojo gives a daily item, just click on the Moodah. Also, the bountiful mine gives a bunch of reagents like ores and gems daily, just click on the mine cart. You can collect from them even if they are in someone else's house/castle.
And some players are just silly and place multiple clickable items in the same house (i.e. gem mine, treehouse, fishbowl, shinobi Dojo, and teleporters to other houses with objects to click on). This makes it possible to get lots of free drops quickly!
