Modular is Sh!t you should get a Banjo!
Looks like a pretty sound rack to me.
-- wishbonebrewery
Agree, banjo's rule.
Are you using the ES-9 to connect with VCV rack or other software? If so, this thing looks pretty beastly and you can get what's I'd say is missing virtually. However, if not, or just because you have the blank panel spaces, I could suggest the Batumi expander, which gives you access to more LFO shapes, and some other utilities or random voltage generators? Things like mutes or routers might make this more interactive and fun to play, as well.