Available until 10:00 AM EST tomorrow, you will be able to claim this solitaire meets roguelike RPG by logging into your Epic Games account and navigating to Solitairica's Store Page.
With Solitarica entering the ring, that only leaves two more days of free games. The final two games will likely be Torchlight II tomorrow and Jurassic World Evolution, thanks to a leaked list shared on Twitter awhile back.
If you have not already claimed the game, make sure you head over to the Epic Games Store before it leaves tomorrow. Even if the game does not look impressive, you should still claim it. You never know, one day you may decide to give it a try and end up liking it!