The majority of GA alternatives use cookies, which of course do allow tracking returning visitors. If you're asking what GA alternatives don't use cookies but

The majority of GA alternatives use cookies, which of course do allow tracking returning visitors. If you're asking what GA alternatives don't use cookies but DO allow tracking returning visitors, then the list gets pretty limited. The only tools I review in my book that don't use cookies by default but do allow tracking of return visitors are Clicky (which does it with User Agent + IP) and Visitor Analytics (which does it through fingerprinting). User Agent + IP as used by Fathom and Plausible could track returning visitors if they didn't rotate their salts, but if they did this then you would need to ask for consent to track. IMHO, the issue that determines if you need to ask for consent is this persistent tracking, not the technology you use.