An “oxymoron” is the combination of conflicting words, such as “liberal Republican” or “old news”. Is there a word for a combination of words that are redundant, rather than conflicting, such as “free gift”?
Yes. Pleonasm:
Tautology?
Don’t start a civil war, now.
Redundant tautological pleonasm?
Repetitive redundant tautological pleonasm?
Smør på flesk
My fave is “true facts”.
Redundancy.
For lunch, I had a salad with Jumbo Shrimp on it. 
That’d be the Oxymoron Salad, I take it?
Someone on this very board said it wasn’t a Caesar Salad unless you stabbed it 23 times.
My long-time favorite is “general consensus of opinion”.
Which really is saying the “general general consensus of opinion”