We get the last three Regional Coins in the game, get the last two seeds planted, then start hunting for even more Power Moons in the Mushroom Kingdom.
The Music List is one of the most interesting things in post-game. Just press the Minus button, then press Y to enter the menu. You can then go anywhere with any music from the game that you want, so if you want to go everywhere with the Steam Gardens theme playing, go nuts.
There is a scarecrow near Peach's castle that lets you get on the roof, and there is another on the roof that allows you to get to the center tower and climb all the way up to see the entire kingdom.
You can drain the moat around the castle. Just go underwater and throw your cap at the four stakes to empty it.
Power Moons
1. Perched on the Castle Roof - This Power Moon is above one of the towers of Peach's Castle. You can backflip and then hat toss jump to reach the spire to climb up it and get this.
10. Found at Peach's Castle! Good Dog! - Go up to the dog at the fountain and follow him around to find a bunch of coins, then take him to a small hill near the Odyssey. The dog will find a glowing spot, which you can ground pound for a Power Moon.
12. Herding Sheep at Peach's Castle - To get this Power Moon, you'll need to find six sheep and bring them back to the sheep pen in the southwest corner of the kingdom. Two are near the Odyssey, one is near the pen itself, one is in the Goomba Woods area with the brown dirt, one is near the well containing the 8-bit area, and one is near the rocket near the Goomba Woods. Bring them all back to the sheep pen for a Power Moon.
16. Love at Peach's Castle - You'll need to drain the castle moat, then head to the Goomba Woods checkpoint and make a stack of at least eight Goombas. There are ten in all, though, and you can use all ten if you want. Take the stack of Goombas back to the lady Goomba at Peach's Castle for a Power Moon.
17. Toad Defender - There is a Toad near Goomba Woods guarding a Power Star, and he will mention that he is keeping it away from the Goombas. Take control of a Goomba and bring it back to this Toad to scare him off and get the Power Moon.
19. Jammin' in the Mushroom Kingdom - There is a Toad near the fountain near the Odyssey with headphones on. If you talk to him, he will tell you that he is looking for a song with the theme "flat 'n blocky classic." This will introduce you to the music list, which you can access at any time with the Minus Button and pressing Y. Any song with "8 bit" in parentheses in the title will do, and when you select one of those, you'll get this Power Moon.