Any way to create the migrations without the new experimental feature prisma migrate ?

You can use introspect and your own migrations library if you do not want to use Prisma Migrate.

Yes I know but how can you manage the migratins ? What kind of tool are u using for that ?

You can use something like this: https://github.com/salsita/node-pg-migrate for Postgres.

The introspection is the last part so that's the less important thing. I'm asking about the tools/libraries to manage the model and the migrations.

You can use the above tool for migrations.