Uno works well for us.
Random board games from the public library. Some work, some not, but we don't spend money to figure it out.
8 year-old can already play games like Pokémon Trading Card Game. While that's absolutely a money sink, it encourages them to read and do simple math.
I've always wondered if two people could play a kind of "Hangman", but with five-letter Wordle words. (Kind of like the paper-and-pencil version of Mastermind, but with letters...)
Here's a video of people playing it. https://www.youtube.com/watch?v=htdtUDepcok
The objective is that you both say a random word. Then both those words together make you think of a different word, and you keep going until you finally both come up with the same word. It goes on really wild tangents, so how you start has nothing to do with how it ends.