Can I increase the number of country list from AWS WAF rule configuration from 50?

It seems we have geo restrictions of limit 50 countries at maximum thus this is not possible with individual rule.

Having said that the work-around to this issue is creating two Geo Matching statements with 'OR' condition and each statements with certain number of country codes you would like blocked.

Below is the JSON format from the console I have tested by creating two geo match statement using the 'Or' condition

"Statement": {
    "OrStatement": {
      "Statements": [
        {
          "GeoMatchStatement": {
            "CountryCodes": [
              "AD",
              "AI",
              "AL"
            ]
          }
        },
        {
          "GeoMatchStatement": {
            "CountryCodes": [
              "BS",
              "BD",
              "BY"
            ]
          }
        }
      ]
    }
  }
}