Use IAM custom roles to manage access to your BigQuery data warehouse - When you’re migrating your data warehouse from Teradata to BigQuery, pay attention to mapping user permissions using identity and access management tools.
Migrating Teradata to BigQuery - Solution series that helps you transition from a Teradata data warehouse to BigQuery.
Teradata to Google BigQuery Migration. Converting the code - This article provides instructions on how to extract the schema of tables, views and SQL Queries from Teradata and convert it into BigQuery.
Transitioning from Data Warehousing in Teradata to GCP Big Data - Article describes how you can transition from on-premises and cloud data warehousing to Google Cloud Platform.
Defining a Reference Architecture for Teradata-to-Google Cloud Platform Data Warehouse Conversions - Describing an architectural framework for conversions of data warehouses from Teradata to the Google Cloud Platform.