Mythical third champion

Been playing a long time with a lot of breaks in between, de-rusting now vs bots and last time I didn't had a third champion to complete my pool.

The 2 that i got was aatrox and renekton.

Both have sustain, manaless, good blindpicks, enough mobility, have utility when behind and they fullfill diferent roles (aatrox as a beefy juggernaut and renekton as a diver).

Is there a third champion that can have similar characteristics of this champions or do i have to have a pool of 2 champions?