I went to Florence last year and found the best vegan ice cream.
Head to Perché no! (translated to Why not!) Rated by some as the best ice cream shop in Florence, this small gelateria offers a range of SFV ice creams made from soy and rice milk. They are easy to differentiate as they are in a separate window, and flavours include vanilla, chocolate sorbet and hazelnut. FYI: THE HAZLENUT IS AMAZING!
Gelateria Vivaldi and Gelateria Edoardo also offer a range of flavours which are definitely worth a try including rum, chocolate and pear!
I've written a blog about my trip which you can see here: https://www.adaptnetwork.com/veganadventurist/vegan-street-food-ice-cream-florence/