These books (S) are (V) the best novels I could find(SC).
Originally Posted by Fame
Note, a better way to form that sentence would be to omit books. I (S) gathered (V) the leaves (DO) into a pile (A).
Ex: These are the best novels (that) I could find.
The relative clause (that) I could find functions adjectivally. It modifies the noun novels.
 James Wong (S) is (V) the fireman (O) who fought the blaze (OC).
Note The farmer (S) herded (V) the goat (DO) into the pen (A).
, sentences  and  share a similar copular pattern, yet in  who fought the blaze
is an (OC). Why is that?
Note also, object complements are used after certain verbs only. An object complement is often found with verbs of perceptions, thinking, or verbs that denote a change.
Object Complement - ICALwiki A way to CHECK if the element following the object is an OBJECT COMPLEMENT is to form a separate sentence using the object and the supposed complement with the verb "to be". If this is possible, then the supposed complement is in fact the OBJECT COMPLEMENT.
- Many people consider Churchill the greatest British statesman.
- We decided to paint our house red!
- They named their child Thomas.
See examples here Syntax Lunacy: OBJECT COMPLEMENT