Handy tool for database/table design?

Hello
I created already a few Airtable database, although I’m still a newbie :winking_face:
Before I start a database and table design, I try to make a drawing on paper, with the different tables, and especially the fields that are linked to another record and those that lookup information in another table. If you get these right, you’re more than halfway :winking_face:
Today I still use pen and paper to get the design roughly and with arrows drawn on paper, I can see the relationship between the fields in the tables, before I start programming.
My question is : Is there a handy tool, cloud-based and free ;), that would make these drawings and the design of the database easier ?
And if this simple tool would have an export to Airtable, so that you have already the database with the relational fields, that would be a great bonus :winking_face:
Thanks for your suggestions,
Michel