Regardless of what champs are popular at the current time, it is always fun playing the underplayed, lower win-rate champions. Just have to choose them intelligently as they are usually niche. Only work with certain team comps against certain team comps type of thing.
Try Zil, Karma, or Janna Support. (Havent seen too many janna lately)
Trundle, Sej, or Shyv jungle. (What happened to Shyv?)
Aniv or Heim mid.
Sion, Poppy, Urgot, Ren, or Nas top.
Mostly champs who were created in season 1 and 2 of league seem to be getting forgotten.
I've also been using Ren and Nasus more often top. Nasus is really fun, especially if left to free farm he gets extremely scary and I mean extremely. Ren is cool too because of the little burst damage combo he has for harass that does quite a bit of damage and the fact that he's packing a little sustain in his Q.
I've really been trying to branch out and learn to play more champs better.