Alrighty, I've done up a bunch of modules. Whilst it may not look it, the modules actually go down into the hull a number of decks (down to about where the hull transitions from sloping outward to inward)
To start with, here she is with no modules installed
Expanded austere accommodation or medical module
'Mothership' module with crane and two LCP4 for expanded peacetime domestic patrol duties
Maybe a little far-fetched, Idk, but a 'Point-defense/Gunship' module, intended for use within a wider taskgroup or convoy. Increased anti-air gunnery with 2 x Oto Melara 76mm (like a compact Horizon frigate in a ways - also aids in increasing shore bombardment capabilities) and an extra Millennium Gun mounted above the hangar.