I have one of those machines too. My grand daughter likes the birds, but I like the rain/storm.
Neat, mine doesn’t have a bird option. I wish it did - the cats would go nuts.
I didn’t think the machine was really doing much to soften sounds until a few nights ago. My big male persian is a purr machine. I love falling asleep with him next to me. But with the machine on, I couldn’t hear him at all. At first, I thought he was sick, LOL! Then I turned the machine off and he was indeed purring away.
A purr would be a nice noise option too ;)