Oranguru is built for doubles, but it is entirely usable in singles. Don't listen to
>>33370507 shittin' ya.
It has nice natural bulk (90/80/110) and a typing which it can use to set up Calm Minds or Nasty Plots better than other Psychic types. You have a lot of offensive options too: Psychic, Psyshock, Stored Power, Nature Power (Tri Attack), Shadow Ball, Dark Pulse, Energy Ball, and Focus Blast.
If you choose to run it with a singles Trick Room build, Inner Focus is great so the opponent can't stall out turns with Fake Out. You could even use it to set up Psychic Terrain if you don't like using Lele or are playing in lower tiers.