Can anyone suggest some combat formulas based on this data?

[Joshua A.C. Newman]

Like I said, I've seen many RPGs and the problem I run into is that their stats usually only reach 20 or some other low number. It doesn't allow for unlimited stat growth (which is important to keep people progressing in the game, setting no limit, and making them get stronger and stronger).

Welcome to the Forge, Jesse.

I think you're approaching this design a little backwards. The above question reveals several assumptions that I don't think you have to make.

Answer these questions and we'll be able to help:

1: What do the protagonists do in this game?
2: What do the players want from the protagonists' actions?

Here are some example answers:

1a: The protagonists fight monsters of increasing scale until they get the bad guy at the end.

2a: The players cooperate against the GM to defeat the adventure that's been planned out.
2b: The players compete with each other to get the most and best monsters.

1b: The protagonists are politicians in a court environment where a cutting remark can kill as well as a stiletto.

2c: The players build a conspiracy theory chart out of premade cards and tell stories for each card they add.
2d: The players build alliances between their protagonists and NPCs and use them against each others' interests.

In question 1 I'm asking about fiction. In question 2, I'm asking about real people sitting at the table playing the game. Those real people might not have the best interests of their characters at heart, depending on the nature of the game.