I've come across several sentences that have a lone subject or object and then the verb without a particle to be heard of. One example is テーブルですか so my question is, do I only need to use a particle when the subject or object is not clear?
In spoken Japanese, subject, object, and topic particles are dropped if context makes the role of each noun clear.
僕テーブル買った is fairly certain to be understood as "I bought a table" without the particles.
In your sentence, even with a subject, no particle would appear between テーブル and です.
could all be interpreted as "This is a table."
If you are describing a quality of something with an "X desu" phrase, no particle goes in between X and desu.