You want to reply to this toot:
DISTRHO 3 band EQ - https://github.com/DISTRHO/DPF-Plugins
TAP has a couple EQs (dunno about GUI, don't have them installed) - https://github.com/tomszilagyi/tap-plugins
Steve Harris has a few EQs (no GUI) - http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html