Hi Dragonite, and welcome to PC.
As Wind Heart said, we have the Battle Center for all competitive battling needs, it even comes with a Pokemon Showdown server built-in where you can chat and battle with fellow PC members. I only got involved with the server back in December but I managed to have a lot of fun there. Definitely check it out, since it has loads of fun battles you can try. The NU tier is very popular there, and also RU as of late. There's also Random Battles for some extra craziness. I'm +OshyHikari on the server if you're looking for me there, and I'd be happy to teach you battling skills anytime.
Wind Heart also directed you to the Challenges section if you want to replay all your fave Pokemon games with a bit of a twist. There's loads of active challenges you'll find there, such as Nuzlocke, Monotype, and loads of other cool ones. Everyone here, both staff and members alike are always happy to lend you a hand anytime. Our NU/W mod duo Cirno and Cid are always happy to take on any questions you have, they definitely won't bite.
Call me Hikari, or Hika for short, and if you need to talk just VM me.
- [supporter]Hikari10[/supporter]