With Trundle its known that there are trolls but what other non-humanoid races live in runeterra?

Animals.

I was hoping for more like ogres or orcs or sylvans or centaurs or goblins or tigerpeople or whatever

Armoured bears, dragons, brackern, giant freaking worms, who-knows-what in the Shadow Isles. Probably more.

They're still adding, and nothings going to be completely the same. Riot has given it's stance on races and species, that they would like to move away from more common fantasy creatures and shed some light on the less seen ones. Sure, eventually they are going to have to add in the common ones, eventually, but I don't think we'll see something as general as an Orc for a while. They just introduced centaurs with Hecarim, so they seem to be expanding. I would personally like to see something like a water nymph or a dryad soon.

Along with the void, there is no limit to creature creativity when it comes to the void, only one checkbox there: scary.

They should add Orcs. Orcs are awesome.

In regards to the void, there is only one requirement needed: "Wanda..."

Minotaurs, Undead, Undead Centaurs, Udyr, Brackern, Wyrms, Mechanicals, Mundo, and a Phoenix.

Udyr and Mundo are human. Completely insane, but still human.
And Undead Centaurs count among Undead.

And Mechanicals aren't monstorious beings. They're constructs.