My list will be
- bitcointalk ( because interest here focus on crypto)
This is the main forum of all cryptocurrencies and there is a big wide exposure if a project will be advertised here.
- telegram ( active users on ICO channel can gives you an idea how much demand and support has been getting from the community the ICO is)
Nowadays each ICO does have its telegram channel because its one of the best way to ask and give information to their participants.
- Facebook/twitter (just simply there's a million of users there)
Facebook is a good one even though they restricted paid advertising but every project can still their profile and facebook page for their ICO. Twitter is without a doubt does have a lot of crypto followers.
- youtube (easy to understand how the project works with videos)
And also a tutorial on how to invest.
- medium (last not but the least because serious crypto investors tend to read carefully most of the ICOs being posted there )
I haven't used medium yet but I've seen there are many people who are staying there too.