On iOS and macOS, it's hard to beat NetNewsWire.
On Android, I use Feeder.
On Windows and Linux, go for QuiteRSS.
If it's free and open source and it's also software, it can be discussed here. Subcommunity of Technology.
This community's icon was made by Aaron Schneider, under the CC-BY-NC-SA 4.0 license.
On iOS and macOS, it's hard to beat NetNewsWire.
On Android, I use Feeder.
On Windows and Linux, go for QuiteRSS.
In case anyone's looking at this 3 months later, I finally got down to getting an RSS Feed Reader and downloaded NetNewsWire on my iPhone.
Newsboat
I am not one of these terminal wizards. I do heck of a lot in the terminal, though. One thing I never thought I'd do in browse RSS feeds.
But, a few years back I was in a situation where my only working computer was a Raspberry Pi so I found myself using Newsboat and I realised the big deal.