The following comment is what I usually post when there's a game giveaway. I'll sort the coding later, about to eat dinner. :)
Please check Delenn's threads over in the giveaway forums HERE and HERE for the latest non Steam and Steam freebies. Also for the latest Steam sales check THIS Steam database site out. You can list the games in 'price' & 'percentage off' by clicking the headers. If you link SteamDB with your Steam account, all games that you already have will be highlighted in green. When there are Steam games being given away, you'll see 100% off.
Don't forget to check Indie Gala's freebie/showcase section HERE, then click on the Showcase header, selecting freebies from the drop down menu; recent additions include Pixel Puzzles 2: Christmas ( a traditional style jigsaw puzzle game), North (asylum seeker game), Snowball (A more "discovery-based" approach to pinball. Learn the secret rules of the board to access hard to reach places and rack up HUGE SCORE BONUSES, which are generally agreed to be more important than any other current event in the real world) and the full version of Die Young (you play as Nehir, a field agent of a well-known political party. The party's agenda is to deconstruct and eliminate Brother n.1, the leader of Island's community); we were previously given the prologue version, (which is still available free) Recent games such as Distortions, Dino Run DX, Cheap Golf, Kill Em All, Dead Hungry Diner and Contract with the Devil have now been removed. All remaining freebies can be found in the showcase section (around 100 are available). Not all games that go into the showcase remain free, so you should grab them as soon as you can.
Check out the latest Epic Games freebie HERE. You'll find the weekly game and usually what to expect next week as well as several other permanently free games such as Rocket League, Genshin Impact, Rogue Company, Dauntless, Idle Champions of the forgotten realms, Paladins, Warframe, Neverwinter, Star Trek Online, World of Warships, Trackmania, Cave Story's Secret Santa (also available via GOG), Heroes & Generals WWII, Scavengers, Valorant, League of Legends, Teamfight Tactics, Legends of Runeterra and Core. Most of these are free to Play, but with in game purchases. You can play them all free, but without the in game purchases you'll find them either very grinding, or hard to win. Some do give away free stuff such as Idle Champions; and, if you have Amazon Prime Gaming, you may find you can get some of the add-ons/DLCs or in game purchases for free.
There are several thousand (+) free games available on Steam, though if you go to the free games section you'll only find a few hundred listed. Many of them have been removed from the Steam store over the years, but, because some Steam community members have added them when they were available, they are still detailed in the Steam database. Because they are free, you can still access these if you know where to look and then add them to your account. Initially I tried just adding ones I liked the look of, but it was so time consuming and I reckon I only looked over less than 1% of the games available; so, decided just to run a handy script and let them all be added. A friend told me about it some weeks ago. He enjoys running the script for one run every morning while he takes breakfast. Because Steam rate-limits the number of games you can add in any one hour, the script will only add 50 games at a time. He then looks them over and then removes the ones he doesn't want in his library; then repeats the next day with another 50 while having his breakfast. He's been doing this for several months and said it's quite exciting discovering what games you can get for free.
Many of the games are decent first attempts by fledgling developers; for example I was playing one of them that I'd added some days ago called Sinking Simulator; (I had a free standing alpha version of the same game a few years back, but the
latest version is a fully fledged game that has been expanded and the graphic improved significantly) . With this game you can model the sinking of various ships and other floatables. If you like destructible physics based games, it's quite entertaining and an ideal coffee break game. It includes a level editor and access to over three thousand Steam WORKSHOP items that include models of famous ships and other models that you can use to create your own ships. This is just one example from the several thousand totally free games you can add to your account. (check out the three videos on the Steam page HERE for an idea of what the game is about). There's also a few guides that you'll find HERE
There is a Script you can use in conjunction with SeamDB that will add every free game into your Steam account (It doesn't install them, just adds them to your Steam library). I will be posting details of how to claim all those free games over in the forums when I get some time to myself. At the moment things are really manic for various reasons, so it probably won't be until the new year. I will be posting a link to the thread once I've posted it. :)