As you may know, I prefer to buy my PC games on Gog. While I do not buy that many anymore, due to a lack of time mostly, I sometimes have the desire to replay a classic game or try a new independent game that I heard about.
Gog holds sales year round, but the Summer Sale is always one of the largest. A good opportunity to purchase one or two games that have been sitting on my wishlist for some time.
Gog says that the Summer Sale 2025 offers over 8,000 deals with discounts of up to 95 percent. Here is the main link to the sale. It is probably a good idea to use the excellent filters on the left side of the page to reduce the 161 pages of games that are on sale.
You can, for example, hide DLC and extra listings, set a price range, or pick genres, features, or tags.
As always, here are some of my suggestions:

One of my all-time favorites. A turn-based strategy game with lots of variety, short but intense levels, lots of replayability, and fun.
You control three units and are tasked with defending cities and the earth population against an alien threat. Each of your units, mechs mostly, have different unique abilities, that can be expanded as they gain levels and new equipment.

Faster Than Light plays in space. It is a strategy game that gives you command of a ship and a diverse crew of aliens. You can upgrade the ship, encounter enemies and wondrous things. It is randomized and rogue-lite, and if you do not mind the graphics, one of the best experiences you can have while playing a game.
Day of the Tentacle Remastered

The remastered edition of the 1993 sequel to Maniac Mansion. It is a classic adventure game by LucasArts that has lots of humor. Unlike Maniac Mansion, which asked you to pick three characters out of a selection, you always play the same three characters in the game.
Your task is to prevent that an evil mutated purple tentacle is taking over the world. Involves time traveling, lots of fun.
Now You: have another pick? Let me know in the comments below.