According to the newest post on the Yacht Club Games website, a whole hoard of Shovel Knight games is coming out on December 10, 2019. First, the studio is releasing two new games on this date: Shovel Knight: King of Cards and Shovel Knight: Showdown.
Shovel Knight: King of Cards is the final installment to the Shovel Knight series and focuses on King Knight, with the studio claiming it's their biggest game yet. It releases on all the platforms the Shovel Knight series is already on, including older consoles such as the Nintendo 3DS and the Nintendo WiiU. Shovel Knight: Showdown is a four-player platform fighter where players can compete against each other in duels and gem collecting, or work together to take down AI opponents in Story Mode. Showdown is also releasing on the same platforms as the original, except it will not be released on the PS Vita or Nintendo 3DS.
The final release slated for December 10 is the physical edition of Shovel Knight: Treasure Trove, which includes: Shovel Knight: Shovel of Hope, Shovel Knight: Plague of Shadows, Shovel Knight: Specter of Torment, Shovel Knight: King of Cards, and Shovel Knight Showdown. Though it was initially available digitally, Shovel Knight: Treasure Trove will have a physical release on the Xbox One, PlayStation 4, and the Nintendo Switch. The blog post mentions that the Shovel Knight: Treasure Trove physical edition for the PlayStation 4 will unfortunately not release until early next year due to a manufacturing error.