I'm thinking some alternate version of the English Civil War (alternate because obviously the lack of French unification will have enormous effects on European history) which divides the pre-war Kingdom of England between a Commonwealth/Republic of England in the South and a surviving Kingdom of England in Wales and the North, and where the Kingdom and the Commonwealth fight on for a long time but neither of them achieves success and eventually they give up; in this scenario Ireland and Scotland would remain independent (getting rid of OTL's Anglo-Scottish personal union won't be too hard and Ireland might successfully assert its independence from Protestant England in the *English Civil War). (Various more extreme suggestions, like Cornish independence, ignore the inconvenient fact that the vast majority of Cornwall has very little Cornish nationalist sentiment and so they're probably unviable. Welsh independence is difficult when Wales has been unified with England for many centuries and, more importantly, is right next to England.) That gives only four states in the British Isles (more than that is hard because of the British Isles' historical very low population compared to anywhere on the Continent), but I hope it's enough for the OP.
If Austria wins several wars against rival German powers and there's some Hundred Years' War-esque invasion that solidifies German national identity, it might make the Holy Roman Empire (more realistically, just parts of it) into something more centralised and substantial. That'll almost inevitably lead into a boringly German-dominated Europe from very early on, by sheer weight of population, but perhaps the northernmost parts of Germany and/or the Rhineland can go their own way.
Italy is the really hard one; with the papal states existing and religion remaining so important, it'll take the coming of the age of nationalism to end that (as it did IOTL), short of absurdly early PoDs that will render European history unrecognisable.
French balkanisation is easy; the problem is that the peoples of what became France weren't very linguistically unified at all, so without French unification then many parts of OTL's France won't regard themselves as French at all, so later French unification probably won't work.