Having a new module purchase in mind is a great thing but it can definitely distract from what you, I, really need.
I need a Arturia Beatstep Pro for some out-of-case sequencing, simply because the same capability in-rack would cost a fortune and not be as good as external sequencer.
Instead of thinking straight, I have a module in mind but then also all the modules that would benefit that module in a line in front of it.
Proper a Case of 'Up here for dancing, Down there for thinking'
Enjoy your spare HP, don't rush to fill every last space, this is not like filling sticker books. Resist the urge to 'complete' your rack, its never complete so just relax.