I'm reviewing my list of kanjis to limit myself to JLPT N2 and below for now, but I find that some of them aren't in any JLPT level yet are quite common. Examples:
and I'm only starting so I'm sure I'll find more. I use jisho.org and this list also agrees: https://www.nihongo-pro.com/kanji-pal/list/jlpt Why is that? And given that common kanjis seem missing from the JLPT levels, are they a good reference for studying?
See, the jouyou kanji list is no less imperfect. Why simple and common kanji, such as 嬉, are suspiciously absent is anyone's guess. As for the JLPT list, well, you've pointed out some grave offenders yourself.
So are such lists a good study tool? If you're just preparing for the JLPT, and you're positive that only the kanji on those lists can appear, then keep at it; however, in general, I don't recommend this type of approach at all. As long as you're consuming media in Japanese and learning vocabulary in context, you'll amass so much vocabulary that the N2 multiple-choice kanji section will seem trivial in what it asks of you.
If you're serious about learning the language beyond just passing the N2, then do keep the jouyou list in mind as a guide or a reference, but nothing more.
