Do all verbs come in pairs?

Hello, I'm in the process of learning some pairs of transitive and intransitive verbs. However, there are some verbs for which I can't find a pair or that are not identified as either transitive or intransitive ( for example iu, oku, isogu).

So I have two questions:

Do all verbs come in pairs?

And, if not, do these single verbs take either が or を depending on the sentence?

Thank You.

No, not all verbs have pairs.

The particles you use depends on the verb (there are of course more choices than が or を, and furthermore it can change with conjugation), so there's not a single answer. Use a dictionary which shows example sentences, that's a quicker way of working out how the verb is used.

One thing to look out for is that with some motion verbs を is used but doesn't mark the direct object (so this is not considered transitive). e.g. 公園を歩く

Thank You.