Xbox Game Pass titles will usually rotate in and of the catalog at month's end, so six titles will be departing come July 31. Soon leaving the catalog will be DiRT Rally, LIMBO, Overcooked, Pharaonic, So Many Me, and Ultraton (via True Achievements.)
As usual, it is best to finish these games before the July 31st deadline to ensure that you won't lose access. You also can opt to pay the full price for each of the games if you want to keep playing after July, but that is completely optional.
Microsoft has not yet announced the Xbox Game Pass lineup for August, but that is due to change by the end of this week. If you're not already an Xbox Game Pass subscriber, you can try it out now for free for 14 days. If you happen to like the service, you can currently take advantage of an offer where you can get 3 months of the service for $9.99.