Reading data from oracle 8 in 2019
List of method (I know) to transfer data from one Oracle DB to another


database link
Data Pump (expdp/impdp)
exp/imp
SQL Developer -> Migrate Database
custom script ( eg PERL )
CSV/XML Dump and Import
ETL software (eg Informatica


The largest problem of any of those is "what is supported?".

*Database Link is only "supported" between a "2 major versions".  eg: 10g can talk to 8i but 11g can't.

Data Pump should support a lot larger range.  I don't think expdp was made available until 10g.

Classic Export/Import is limited on what is supported.  Luckily, Oracle Support has a document for "what works with what".  Ask your supervisors to get a copy of Doc ID 132904.1 for you.  YOU MUST HAVE A VALID SUPPORT CONTRACT TO ACCESS THIS DOCUMENT.

SQL Developer might help you out.  You'll need to import a JDBC driver that can talk to 8i.  You may have to contact Oracle Support to get that driver.  (latest is a 10g driver)

custom script can have problem if you cannot load two different drivers simultanously.

CSV/XML concept needs to be carefully thought out.  beware of \n.

ETL Software still needs the appropriate driver.

REMEMBER

10g is the latest that can talk to 8i.
11g is the latest that can talk to 9i.

Oracle Support has all the knowledge of "what works with what".

Update (2019-09-23)

Someone figured out how to import the Oracle 8i JDBC thin driver into an 18c database in order to run queries against Oracle 7.

https://community.oracle.com/thread/4268386