Standby essentially turns your iPhone into a bedside clock while it's charging – it can show the time and date for example, or a selection of photos from the phone gallery.
Apple Music already lets you add artists as Favorites, but that's been expanded to include songs, albums, and playlists in iOS 17.1. Any tracks that you've previously 'loved' in the Apple Music interface will be converted into Favorites.
Another change made by iOS 17.1 is an improvement to Airdrop transfers: you're now able to continue transfers over Wi-Fi or cellular networks, once they've been initiated.
There's an option called Photo Shuffle that you can use on the lock screen of your iPhone: you can find it by pressing and holding on the lock screen, then tapping the plus button, then picking Photo Shuffle.