What are the "really bad" nursery grime tunes?
(quotation marks not specifically directed at Queen of Sheba - though I'd be keen to hear your opinion - but just for the general consensus that there are a lot of them, always supposed to be much worse than "Migraine Skank" or "Jump In The Middle and Skank" (which I really like!) or "Head, Shoulders, Knees & Toes")
"Ring-A-Rosy"? I haven't heard that yet, nor the Donaeo version.
Are there any others?
Without having plumbed such hypothetical/actual depths, I mostly feel warmly disposed to all of this stuff. It puts me in mind of that period of proto-grime crews being silly as often as they were scary, stuff like "Course Bruv" and "Bouncin' Flow".
And my favourite verse on Static's "Charge (Remix)" was always Mighty Mo's...
Well, 079 Me by LJ and C.Los is pretty awful, albeit in an entertaining sort of way. Ring-A-Roses imo is almost as bad, but bear in mind I've only heard it a couple of times so far. It actually strikes me as something that could put people off on the dancefloor in certain circumstances, very off-kilter. As said before I feel the Migraine Skank is much more enjoyable as a dance than a song, but should note that increasingly it's stuck in my head.
Ghetts - Came In The Game that was posted upthread isn't terrible as such, but is certainly awkward sounding, sort of like a first draft or blueprint for something that isn't finished yet. Although that's perhaps not so much nursery-grime in the novelty sense as it is just a general attempt to mix funky with grime MCing..
Also, some may disagree with me, but I reckon Too Many Man by BBK is pretty weak; the lyrics and the music both obviously had the potential to be good, but they seem to have come off just a bit half-baked. But again, there is probably a debate to be had as to whether it's ful-blown funky, or funky-influenced grime, and yadda yadda yadda.
After all that griping, I should say that I'm really quite feeling Maxwell D - Blackberry Hype!

Best of the bunch so far along with Heads, Shoulders.. and Tribal Skank I reckon.
I do get the impression that there are more of the poorly-rated tracks out there, and am unsure how hard I want to press in trying to hear them!
As a general point - although obv for each individual DJ it's up to them to decide what records they want to play, I do think that any semi-official, organised campaign to push these records/artists out of the scene would be very silly indeed, and show that no lessons have been learned from the grime/garage split. In many ways I find the concept of these tunes fun and endearing, think the comparison to Genius Cru type garage-rap is an apt one, and the return of these novelty-dance themed tracks has quite a summer-holiday-song vibe to me. Don't mean that as an insult at all - it probably relates to the role Ayia Napa has had in the development of the scene in some way. But Simon78 I think used the phrase 'botched together' to describe some of the tracks, and I think that's very accurate, people don't fully know how to rhyme over the rhythms yet.