I think the most obvious are games like Scrabble and Upwords, where the goal is to make words.  Usually, with that sort of game, I make vowels free (there's a pot of vowels any team came pull from) to make it easier for kids to spell words.

UNO can be a good way to practice numbers and colors for younger kids.  You make them say the color and number when they play the card, or they have to take two extra cards.

Guess Who can be a good way to practice describing people ("Does he have long hair?").  It's meant for two players, but you can make it a two team game.

I've played Cluedo before with students.  You just practice the key phrase ("It was X in the Y with the Z"), the names of the rooms, and the names of the weapons, and the game's story as well.  You could make a whole lesson around it if you finish the book early or something.

Monopoly is alright if you play with the auction rules.

And you could always buy something like a ring toss game and do flashcard review with it (if the kid correctly identifies the thing on the card, he/she gets to throw a ring).

If you have large classes, you either need to buy multiple sets of the same game or split the kids off in groups (letting one group play the game for so many minutes or the day, then letting another group play for so many minutes or the next day).

I think this also depends on how large your class is. If you have a small class you have a lot more options- anything really.

But larger classes are harder to control and keep all involved in some of the board games out there. I have ~30 kids in a class...

I have dice in my class room that I make games up with.
I have whiteboards for each group, that work for different games.
I have a regular deck of cards, you can do a few different things with this.
I have a bag of letters, I think it is called 'word ball'. Not sure what the actual game was (it was already at my school). But I use it just to draw letters and have them do things with the letters.
I have a few Jenga towers (you can write English words on them, or have a WS connecting words to numbers on the blocks. Make them write or tell a story).
My mom sent me these "Story Cubes". It is a bag with 9 dice that have pictures on each side. I'm still figuring out how to use them... I'm thinking camp with less students.

I few word games that may work, I've also seen PPT re-creations of them: Boggle, Pictionary, Scatagories, Scrabble,

Twister- if you have a small group and younger kids- colors and body parts.

Those are a few that I thought of this morning. I assume you are asking because you have school money to spend? Either way I would buy things that you could reuse for multiple activities.