The Gallo-Italian languages are a group of minority languages spoken to varying degrees across the north of Italy; they are a subgrouping of the Romance languages. They include languages like Piedmontese, Ligurian, Lombard and Emilian-Romagnol. The subfamily as a whole has a few million speakers still (the exact number is unclear), but the areas in which they’re spoken have seen significant language shift towards Standard Italian, meaning that their present speakers are largely elderly people and/or in rural areas.
This group has undergone some phonetic changes from Vulgar Latin similar to the Gallo-Romance languages, like the loss of most final vowels (excluding a) and the shift of [u] to [y]. However, unlike them it has taken its pronouns from the accusative ones of Vulgar Latin (like Standard Italian did). The “dividing line” between this group and the Italo-Dalmatian group to their south is generally considered to be the La Spezia-Rimini line, the boundary between languages that pluralise by adding -s (to the north) and languages that pluralise by changing the final vowel.
Venetian is sometimes considered a Gallo-Italian language, but it also shares traits in common with the Italo-Dalmatian languages to its south and east, and can also be considered just its own thing.