I am afraid, that you won't be able to find much alternatives in the size of 75mm. I tried and found only one type worth trying. You may have better luck.
Thanx for your reply, I busted the tip off of one of my props and can’t find my spare set. So I was curious about my options for an upgrade! I have a IDEA drone also but it’s not operational at the moment, the company sent me an entire set of motors for an upgrade free of charge. But I’d prefer to fly the Tello, hands down it’s a remarkable drone!
I would be interested as well in a props mod that makes Tello more quiet and found at least this as a hint:
However no idea about any downsides of this mod or where to get such props without taking it from a totally different drone. These blades are also much shorter which would give more possibility for any other mods on top of the drone cover - like a raspberry pi zero w with a camera or other equipment which then was out of risk of being hit by the longer stock blades.