Darius and Tryndamere can pretty much get ahead only by farming, if you don't fall behind you should still be able to be relevant if you farm a lot. Tryndamere is probably the best splitpusher in the game and Darius can be pretty strong in teamfights with the right comp. Renekton is about early game, don't be afraid to go in early with your E in, WQ, E out.
If you like Darius and Renekton, Illaoi and Nasus look a lot like them in playstyle, althought Nasus relys more on farm than the others. Otherwise, They all have amazing damage with few offensive items, can take multiple foes at once, but lack ways of engaging fights and mobility. They are also weak against enemies that kite well.
Lux and Veigar are burst mages, althought Lux has a great artillery potential with her E during sieges. You might like
, less complicated, better CC but shorter range. Also
are very fun to play and can burst down targets but harder to play than the others.
Hope I could help! Feel free to ask anything if you need to.