InfonityForReddit is still going strong and doesn't have ads. You have option to help dev pay their fee or compile your own apk with your own key and use it for free. It doesn't change fact that both service and community is mostly cancer..
I only ever got one ad in RIF, repeated in every spot. I think it was an app for organizing decks in TGCs, but as I don't play any TGCs, I never bothered to investigate. As with every other ad on the internet, I only interacted with it by accident.