Elise

Elise is a strong early game champion that has good cc and burst which Ekko struggles against. She has a ton more early game agency and can win the game before ekko even has the chance to have an impact. You can't beat elise in a 1v1 early. You should either path away from her and and try to impact the other side of the map, or path to her and try to countergank or protect your laner(s) from a dive. Elise is great at diving even very early on and Elise players will dive your laners if given the chance. You can't simply powerfarm when playing against an elise. You have to try match her or trade on the other side of the map.

Rek'Sai

Rek'sai is a strong early game champion that has good cc and burst. You can't beat Rek'sai in a 1v1 early on. Rek'sai has a lot of different jungle paths to choose from so try to get vision on her and track her so you can cover your lanes and lessen her early game impact. If she cant snowball the early game rek'sai falls off later on and she's relatively weak in teamfights.

Nidalee

Nidalee is a very strong early game champion that will invade you. You can't beat her in a 1v1 early so you have to get vision on where she starts and on river so you will know if she invades you. If she invades you shouldn't contest the camp(s) unless your lanes can move first. Try to stay as even as possible with her in the early game and she will fall off later.

Hecarim

Kha'Zix

Kindred

Maokai

Udyr

Zac

Rengar

Amumu

Vi

Diana

Bel'Veth

Evelynn

Graves

Karthus

Kayn

Lee Sin

Lillia

Fiddlesticks

Nocturne

Nunu & Willump

Rammus

Sejuani

Shaco

Shyvana

Skarner

Xin Zhao

Wukong

Volibear

Viego

Trundle

Sylas

Master Yi

Ivern