It helps if the project is also available on major marketplaces, specifically Steam, Google Play, Apple store, etc as these places are more strict about uploads.
If there is something specific you are worried about it, you could ask if anyone else has tried it :P
Viewing post in tips on how to tell if a game virus or not?
This only helps, if the other marketplace (or patreon or twitter or whatever) links to the exact same itch account.
They do impersonate the original creators.
So actually, if you see shiny new game on Steam and shiny new game on Itch ... that does not mean that the Itch version is safe, this means, there is a chance, that the itch account is faking it. Especially if you see a paid Steam game here for free... ;-)