Please name candidates for a possible BLACKLIST.json entries

The scripts/find_big_ram/rom scripts could be handy here.

not output for ESP8266, but there is make topstrings and topreadonly

But I wonder if you're compiling with RELEASE=1? If not the optimisations may not happen

Yes, as export RELEASE=1 is a part of my default environment ;-)

Try a simple BLACKLIST.json[{"class":"Waveform","name":"*"}]

make clean && BLACKLIST=BLACKLIST.json make

grep -i waveform gen/jswrapper.c

Result: