Razer is known mostly for its high-end gaming devices, but it also has a diverse collection of accessories. It just launched a very weird one for mobile, the Gaming Finger Sleeve. It's designed to absorb sweat and thus reduce friction on the screen to help you max out performance when playing Fortnite and other mobile games.
The sleeves, which can go on your thumbs or forefingers, are woven from nylon, spandex and conductive silver fibers — meaning they'll work with most mobile devices. It also helps them to absorb sweat while allowing your fingers to breathe, keeping keeping them relatively cool and dry. They're pretty thin at 0.8mm (and hand washable), so they should still give you some sense of touch.
In the words of one of my colleagues, "thumb hyperhidrosis is real, fam," so the Gaming Finger Sleeve could be genuinely useful for some folks, silly as it seems. It could also be a big help in particularly hot or humid environments. In any case, it will certainly mark you as a very, very serious mobile gamer. It's now available for $10.