What is the most used format to save data with type information
Parquet and Avro both support data types (strings, integers, floats, etc). These are the primary file types used for "big data" projects, although your data doesn't have to be big. Apache Spark is able to read both with ease. Having said that, I'm a big fan of keeping data in a SQL database (e.g., MySQL or Postgres) because that is what they are built for. If you can't re-use the database you're pulling from, could you make your own database locally or on a separate server? I would try using a relational database until your data exceeds 50 GB (an arbitrarily "somewhat large" size), and then I would use Avro or Parquet.