Anyways, here's a list of every Twitch Chat game I could find, along with the price. And if I've personally played the game, there will be a description of what the Twitch Chat integration actually does. Sign up on the email list and get notified as soon as I see or hear about a new one.
Choice Chamber by Studio Bean Games (2015)
Possibly one of the first games ever built specifically for Twitch, Choice Chamber lets the viewers decide if they want to help or hinder the streamer. Most of the interactions involve voting on a situation. So the game says "Time to upgrade that weapon! strength | speed | crits" and everyone in the chat votes on what they want. There are also sections where the chat gets to directly influence the game, such as the Tetris-like room where players can pick a location to drop a block. Depending on what the chat types, the streamer will be able to easily ascend a staircase, or be crushed to death by blocks the chat dropped. Still enjoyable after all these years.
Party Hard by Pinokl Games (2015)
Legend of Dungeon by Robot Loves Kitty (2015)
On it's own, Legend of Dungeon is a very fun, dungeon-crawling roguelike. But once you add in the Twitch chat connection, things get ridiculously fun. There's a separate app (Legend of Dungeon Masters) that lets viewers gain currency and spend it on spawning monsters, loot, or a variety of other things, and it also allows actions through the Twitch Chat connection. A really unique experience at a great price.
Recursion Deluxe by Ursa Games (2016)
Ultimate Chicken Horse by Clever Endeavour Games (2016)
This game is incredible. A couch-multiplayer platformer where you simply need to get the end, but every round, everyone can throw one object onto the map. Sure, you can add platform pieces and boxes, but you can also add black holes, bow and arrows, and rotating buzzsaws. It's a genius couch multiplayer game. The twitch integration is small, but it allows viewers in the chat to vote on what piece they want to give as an option for players.
One Troll Army by FlyAnvil (2016)
One Troll Army is a tower defense game where the streamer is a giant troll in charge of defending a goblin town, and everyone in the chat controls AI characters trying to kill the troll and destroy the town. The chat commands are pretty straightforward, and they tell the AI what to do. Viewers can select a character class, tell their character head to a point on a map, attack the troll, attack the town, etc... It's worth noting that in 2018, the developers said they'd make the game free if viewers in their Twitch chat beat them, and the viewers won, so the game is now free on Steam!
Clustertruck by Landfall Games AB (2016)
Doodle WHAT?! by Poor Ugly Dwarf (2016)
Move or Die by Those Awesome Guys (2016)
Dead Cells by Motion Twin (2017)
Dead Cells is a fantastic roguelike in the vein of Metroid / Castlevania, and it has some really, really interesting twitch integrations. Every level, someone can type "!pickme" to be Captain Chicken for a round. Not only do they get to see their chat spoken on screen, but they also control whether they want to give or withhold the healing items. The chat can also pick how the character levels up when tomes are found, vote on events to happen, and they can open special chests by typing "!pow !bam !biff". Dead Cells really does Twitch chat integrations right.
Domina by DolphinBarn (2017)
Domina is a very thematic game about creating and a team of gladiators, and managing everything from training to actual fighting. The Twitch chat integrations are pretty light on this one, but one nice feature is that the game takes the names of all the gladiators (friend or foe) from the usernames of random people in your chat. Also, if a gladiator surrenders, the chat sometimes has the power to give a literal thumbs up or thumbs down. And while fights are happening the chat can cheer or boo to change the amount of rewards the streamer gets.
Kingdoms and Castles by Lion Shield Studios (2017)
A cute little medieval, city-building game where you grow your city as you also protect it from a variety of disasters and attacks. Twitch chat integration is pretty standard - every so often the game sends a poll to the audience to decide if the streamer gets a perk like a resource boost, or if something bad like a dragon attack happens. It seriously alters the gameplay based on how good or evil your viewers are, so that alone makes it worth a look.
Marbles on Stream by Pixel by Pixel Studios (2018)
Marbles on Stream is the digital version of having marble races as a kid. There's virtually no strategy and no skill involved (except for Royale mode), but it is insanely fun and addictive. The game supports up to 900 people in the chat playing at the same time, which is unbelieveable. Chat integration is simple - in the lobby, viewers can vote on what game mode and stage they want. Then when the game is selected, viewers can type !play to add a marble to the board. Once the game begins, it's a mad dash to the finish. Simple perfection.
Rimworld - Twitch Stories by finally88 (2018)
Free mod for Rimworld ($35)
If you already have the fantastic sci-fi sim RimWorld, you may not know that there is a mod that allows for Twitch Chat integrations! The basic idea is that every so often, an event will be happen in game for the streamer, and the chat will get to vote on what event they want to see happen, good or bad. Maybe they want random NPCs to show up, or bandits, or an environmental disater. Either way, it allows for a little variability in the games
Stream Games by Brogames (2018)
Stream Games feels a little bit like a tech demo but there are some worthwhile games/apps in here, including a few gems. The Archery, Wizard Dodgeball, and 50/50 floor-drop games are the highlights of the pack for me, and they can scale up to a good number of players in the chat. Absolutely worth a diversion if your streaming audience is 50 viewers or more.
Party Hard 2 by Pinokl Games (2018)
The 100-Player Twitch Chat Party Pack by Board Game Fight Club (2019)
I made this! There are a total of 4 games and 9 game modes in the pack that let a streamer play with, or against, up to 100 people in their Twitch chat. Each viewer can join and control their character entirely via Twitch commands. And if you're a streamer that needs to leave for a quick break, you can run the game in AFK mode and let the chat play amongst themselves. It's also a Boston Festival of Indie Games showcase game!
Kukoro: Stream Chat Games by Hey Nau Games (2020)
Kukoro should not be skipped. There is a lot of polish on this pack of indie games, and some of them are excellent with a sizable group. I'll be honest, some of the games are more like activites, and others maybe needed some more playtesting, but the games that are great are worth their weight in gold. You won't regret it.
Stream Animals by Smash Bolt Games (2020)
It's cute! Very simple gameplay - everyone picks an animal to randomly place on the board, and every round, random bits of the floor will drop out. Each player can move one space per round, and random events will try to knock the animals off. Last animal standing wins!