The next step up would be a GTX 1050 Ti. It would be a very minor step up. It is about 15% faster.
Any other cards are insanely expensive right now. Due to the extreme demand from crypto-currency miners. They are nearly double their normal price right now. Some models more than double. Even the 1050 Ti is over 30% higher than normal.
Anyways, the next appreciable step would be a GeForce GTX 1060 3GB/6GB or Radeon Rx 580 4GB/8GB.