It all depends on your interests. There are, in fact, many communities to choose from if you look hard enough. I'll list some examples here.
1. For newbies, or those interested in helping newbies, @newbieresteemday may be the place for you.
2. @ifc offers contests and a marketplace for Steemians who have services or products to sell.
3. If you just want large communities, you may consier @minnowsupport
4. Minnow-Power, host of @GINAbot, is another great place to hang out, especially if you are interested in the tool they offer.
5. For those who care about overall quality of Steemit, try @steemcleaners, @flagawhale, and @steemflagrewards
6. If you just want some fun pastime, visit [Free Steemit Lottery](https://discord.gg/R4Bdba4).