Summary - I have these:
Green guard infantry + Fists of Mackowskill
Marines (mixed clans)
Red Fesselssorwilon heavy cavalry
Fricklander light dragoons (only 4 figs)
1 battery of green clans' artillery
Chasseurs a pied from Crontaineville
One half-battalion of mounted chasseurs
A battery of militia-artillery
I don't have and am not planning to collect any Methorin/Klagimir troops until I've got a decent amount of the main warfaring opponents' armies (the last two were just additions as allies anyway).
From this it is clearly visible that I need light cavalry at both sides, and I've gone through a bit of a hesitation between choosing some Zvezda hussars above the IS-2s (it turned out to be the right decision with the 'easter egg' bonus). I'm gonna have some Blue clans uhlans as soon as I can, also trying to fetch the Hussars again when in sight and, obviously, I can afford them (an alternate but less glorious solution is Italeri's British light cavalry).
The other thing is: I'm totally in need of Blue infantry (actually any Blue units) so I could make up mixed regiments. I always imagined the Blue infantry with chasseur hats (or whatever it's called) and lately I've ran into the review of the HäT Austrian Landwehr at PSR, and thought these would perfectly make it! Sadly, HäT is totally out of reach in Hungary, so I'm planning to buy one from abroad. Also, it's 60 figures so this might make 2 lesser battalions as well.
Less needed, but way earlier to acquire: Zvezda SYW Prussian grenadiers as Fricklander FNGs and French Cuirassiers as Green clans Royal Guard.
Other news: going to Games Day event next weekend and trying to put my hands on some stuff (it's mostly a non-historical tabletop gaming event as I found out but who knows?)