The best fast-thinking game is a game called Speedy Words. The game contains cards which on one side contain an image, which represents the type of word you would have to say, and on the other side contains three random letters which is what the word you are guessing has to start with.
The way you play is you (to start) flip over a single card, so that the letter side is facing up. Then, you must match the color of the image on the top of the deck (examples of image types are “name”, “profession”, and “country”) to the letter that is in the same color. Look at the above picture to see what I mean. The top card of the deck represents “plant”, which means you must name a plant. The top card is also orange, which means that it must start with the letter “R”.
Whoever says the name of a plant that starts with the letter “R” first wins the card with the letters on it. So if I said “Rhubarb” first, then I would take the card that has the three letters and it and then the next card would be flipped. The player with the most cards once the deck runs out wins.
What makes the game much more fun than similar games such as Anomia is that players are competing to take the same card which means that everybody is actively involved, unlike Anomia where if a player gets unlucky they can get very few pairings throughout a whole game.
It also has more replay-ability because the images are always paired to a random letter, and so while you can keep examples at the top of your mind, they are less likely to come up whereas in Anomia, you can memorize an answer to every card and reuse them every game.