I'm the admin for Find Gamers. Not only is my player-finder still around, I'm pro-actively shopping for a new Bootstrap 4 theme that looks great on smaller devices (phones).
When you use a desktop or a tablet, it is very easy to read long lists of people's gaming interests. However it's really hard to make a website effective on phones, it's just not easy to lay out the information on a tiny screen. Sorry for the mini-rant. Just know there still some player and group-finder's that are trying hard to keep up with changing needs.