'A' followed by 'B'.
This is not a complete sentence: it is just a noun phrase. In the sentence from the link you posted, a noun phrase like this is the subject of the sentence.
"[Common verbs followed by –ing nouns] [are] 'detest' and 'dislike'."
The subject of this sentence is the whole phrase " Common verbs followed by -ing nouns". It is an abbreviated form of 'Common verbs which are followed by -ing nouns'. The verb in this sentence is the 'are' which follows the noun phrase.
[A] [is followed] by 'B'.
['Detest' and 'dislike'] [are followed] by -ing nouns
This is a complete sentence in itself. The subject is 'A', and the verb is the passive form 'is followed'. You can't omit the 'is', because this is an essential part of the structure of the sentence.