Aside from the Zombies of course. So... Book Zero, at the end of Goodminton, Wanda spake saying she was repatching the Zombies... which was better than wasting the juice entirely. That suggests the answer is: Not much. On the other manipulator, she was a novice Caster who'd never spoken to another Croakamancer, plus the Glossary of Book One describes Croakamancy as being able to reanimate Croaked Units among other things.
So other things... Frogs Croak, so do Ravens and co. Perhaps Croakamancy can be used to summon them? Being able to summon, or perhaps even create, Giant Frogs and flocks of Crows and/or Ravens seems like a good option.
On a similar note, the beasts of battle, Wolves, Eagles and Ravens again, eaters of carrion, there's certainly a connection to be made. What could be more appropriate for Croakamancy then calling forth the eaters of the dead?
Angel Summoning. I joketh not, unleashing the Angel of Croak upon her enemies sounds pretty Wanda-ish.
Then there's just killing in general, Wanda's rather good at that, but mainly seems to use good old fashioned muscle power to do it. She may have a nice line in death spells though. Spells that drain the hits of the enemy to restore her own, that sort of thing.
Golems, Flesh Golems, they may fall under the banner of Croakamancy, if it's possible at all, the same could be said for Bone Golems and the like.
Plague, if it exists in Erfworld, would be a Croakamancy thing likely as not.
Finally, the last thought that occurs are things like 'Faded' Uncroaked (Ghosts obviously) or 'Wrapped' Uncroaked (Mummies), I feel this is actually the least likely, as none of the Uncroaked Warlords that were present at TBfGK appeared to be anything other than yer bog standard Zombie Warlord. On the other appendage, at TBfGK she was facing the Arkenpliers which may well be said to have made the creation of special Uncroaked a bit of a wasted effort.
Wanda hasn't been seen using anything resembling any of this, but she doesn't seem to use magic at all these days tbh. Barring scrolls and equipment of course.
Lacking the 'life' thing doesn't seem a problem as Dirtamancers can create Golems without 'motion'. The 'not being Findamancers' thing doesn't stop Hat Mages from pulling things from their hats. So there's no reason why the 'summons' options should be dismissed out of hand.
Are there any other possibilities?