Though dogs are also associated with witchcraft in Europe, what makes Britain stand out is the sheer number of dogs accused of witchcraft (almost on par with cats) and that it also houses the most black dog lore that it’s too coincidental to make such a connection.
Black dog lore is more extensively documented in the British Isles and that in the early modern period there’s a substantial enough number of dogs linked to witches based on the documents I’ve read. There could be other European countries with dog lore that rivals that of Britain.
Apparently France and to an extent Italy and Germany do strongly associate cats and wolves with witchcraft, the latter inspiring werewolf lore, coincidentally the latter three have recovering wolf populations. Wolves were increasingly rare in the British Isles.
Inevitably a wealth of evil dog lore exists in lieu of werewolves proper. Not that werewolves were nonexistent in Shakespearean Britain but wolves were increasingly rare and most dogs were semi-feral so the latter exerted a bigger influence on folklore. Wolfdog hybrids, which can be dark, could’ve also exerted some influence.