Hi Protomski,
Well... there is this section called "Modules" on this Modulargrid.net website, it's full with modules there (thousands of them), any module you don't have yet and that from an HP size perspective fits, is a good candidate, no?
Good luck with choosing a nice module and kind regards, Garfield Modular.
P.S.: Or you specify your question a bit more accurately plus some background information on your shown rack here (do you have that already, is that the last bit of space left, that kind of info) and perhaps we are able to answer your question more specifically ;-)
For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads