IConvention[]

// Some comments here
public class Job1
{
    public MongoContext Mongo = new MongoContext();
    public void Run()
    {
        var data=Mongo.SomeCollectionName.Find(somequery); 
        //Some business logic
    }
}

public class MongoContext
{
    private readonly MongoServer _server;
    private readonly MongoDatabase _db;
    private readonly MongoClient _client;

    static MongoContext()
    {
        BsonSerializer.RegisterIdGenerator(
            typeof(Guid),
            CombGuidGenerator.Instance
            );

        var serializer = new DateTimeSerializer(DateTimeKind.Local);
        BsonSerializer.RegisterSerializer(typeof(DateTime), serializer);
    }

    public MongoContext(string dbKey = "MongoDB")
    {
        ConventionRegistry.Register("Ignore null values",
            new ConventionPack
            {
            new IgnoreIfNullConvention(true),
            new IgnoreExtraElementsConvention(true)
            },
            t => true);

        var connectionString = GetConnectionString(dbKey);
        if (_client == null)
        {
            _client = new MongoClient(connectionString);
        }
        _server = _client.GetServer();
        _db = _server.GetDatabase(db);
    }

    public MongoCollection<SomeCollectionName> SomeCollectionName => _db.GetCollection<SomeCollectionName>("SomeCollectionName");

    //Rest of 78 collections
}