To meet new people, consider Line. It's got a lot of features that allow you to connect with people you don't know but it may not be super popular in your area. It's mostly a hit in the Far East.
Viber and Telegram are used to meet people. Lots of telegram groups. Also Discord is often used to meet people with similar interests. Lots of YouTubers have Discord servers where you can meet new people.
But Tapatalk has heaps of forums you can join and you may meet people there too.