Need to iterate through every single log in a runtime collection and add 1 to the variable "acti"

 var progressCollection = Spark.runtimeCollection("Tribes");

         
         foreach(var d in progressCollection.find({"tribe.name": ""}))
         {
            doc.acti ++;
         }

Getting errors on the "foreach" line. I'm not sure any of it is correct.

SparkMongoCollectionReadWrite.find() does not return an array - it returns a SparkMongoCursor.    Instead try progressCollection.find({"tribe.name": ""}).toArray()

You shouldn't use toArray() for performance reasons.

Loop over the result like this:

var progressCollection = Spark.runtimeCollection("Tribes");
var cursor = progressCollection.find({"tribe.name": ""});
var doc;
while(cursor.hasNext())
{
    doc = cursor.next();
    doc.acti++;
}