were there any PCE games that didn't get back inserts or jewel cases?
Based on the thread title, I fixed that for ya.
There are none that I can think of, other than non-retail promo stuff (i.e. - the special HuCards).
are there any other oddly packaged PCE games?
I can't think of many, but there are a few:
Forgotten Worlds came boxed with an Avenue Pad 3,
Pachiokun Maboroshi No Densetsu came boxed with a pachinko controller, and
3x3 Eyes came boxed with a VHS tape.
Galaxy Fraulien Yuna wasn't exactly oddly packaged, but the re-release version came in a double jewel case with a second disc containing a HuVideo clip; similarly, a few games came in a double jewel case with a soundtrack disc.