https://vger.app/ on both phone and desktop. Not the best for mouse and keyboard but it gets the job done
Two exploration games that I found enjoyable are 廃村巡り | Haisonmeguri and Umurangi Generation.
Haisonmeguri is super short with a few alternate endings, quite janky but the atmosphere and feel of the game are really well done.
Umurangi Generations is more polished and more of an actual game with objectives. I dislike that it’s timed, but that’s the only big criticism I have.
https://toffeeshare.com/ is what I usually use for big files. But both sender and receiver need to be online for the whole transfer. It doesn’t store anything you send on their servers, but that’s a feature for me ¯\_(ツ)_/¯