您可以迭代集合并drop（）

const MongoClient = require("mongodb").MongoClient;

    async function deleteCollections() {
      const uri = "mongodb://localhost:27017/mydb";
      const client = new MongoClient(uri);
      await client.connect();
      const database = client.db("mydb");
      const collections = ["collection1", "collection2", ..., 
      "collection20"];
      for (const collection of collections) {
         await database.collection(collection).drop();
      }
      await client.close();
    }
   deleteCollections();

要删除集合，可以使用DropCollectionAsync方法。
下面是一个示例代码，用于删除由名称数组定义的多个集合：

var client = new MongoClient(connectionString);
var database = client.GetDatabase(databaseName);
var collectionNames = new List<string> { "collection1", "collection2" };

foreach (var collectionName in collectionNames)
{
    await database.DropCollectionAsync(collectionName);
}