Some things I've found useful to add to knoppix from debian bullseye packages:
baobab (which you may know as the ubuntu disk usage analyzer)
xdiskusage
ncdu (netcurses text mode disk usage analyzer)
simplescreenrecorder
(need simplescreenrecorder_0.4.2-2+b1_i386.deb and
simplescreenrecorder-lib_0.4.2-2+b1_i386.deb)
osdclock (package name is osdclock)
osd_cat (package name is xosd-bin)