additional yum repos for 4.3

[nat101l at gmail.com (Nat Gross)]

Hi;
On my Fedora Systems [/etc/yum.repos.d] I have the following repos:
dag.repo
dries.repo
fedora-extras.repo
fedora.repo
fedora-updates.repo
freshrpms.repo
livna.repo

Two questions:
1) Where can I get a .repo file (with centos url's of course) for the
baseic stuff like updates and extras.
1b) Can I use redhat repos?

2) What about the other guys, livna, dag, dries, freshrpms.
Which one of these is safe to use on a production server in
conjunction with the repos used in answer to question 1 above?
2b Are the url's the same?

Thank you all.
nat, a centos newbie.