How to remove all packages installed because of KDE on Ubuntu 19.10

I first installed Ubuntu then I wanted to try kde. So I did

sudo aptitude install --with-recommends kubuntu

or something similar.

When I decided I don't like it, I removed kubuntu and did autoremove.

I recently realized when I'm trying out i3 that everything in i3, terminal etc., are still in plasma style.

How could I 1. find and remove all remaining plasma packages or 2. let i3 use gnome packages rather than plasma ones.

Preferably the first option of course.

Thank you!