Yes, there are plenty of usages of them. Look up the words ידע and אהב in a concordance and you will find that the participle is pretty commonly used.Interesting. Does the Bible ever actually use the participles of ידע and other stative verbs? יודע is used a lot in Modern Hebrew, of course.
You seem to be rather new to Biblical Hebrew. Despite how much you've learned over a short period of time, you still don't have much exposure. The participles of these two verbs are pretty common. Read more of the Bible and you will see them used.I have never come across them. It's always the suffix-conjugation, e.g. ידעתי and זקנתי and אהבתי, all of which convey the present tense, i.e. "I know.", "I am old.", and "I love.", respectively.