Or make your own, in case you don't find challenges that fit your taste/tbr. I search for the ones I need, but I have posted a lot as well. And they're always public, even when the challenge is too personal or specific and I know there won't be many people joining it. When people do join my challenges, it's even harder for me to ignore them.

My current favorite, however, is the streak feature. When this setting is on, it tracks your reading activity, making a streak counter visible from the homepage, where you can further customise your streak parameters just by clicking on it. I'm not good with page goals, so I use this feature just to track my reading habit, setting my streak to one page a day, but it still hurts when the streak goes back to 0. To make it easier and to help you with following other good habits as well as getting rid of bad ones, download a simple habit tracker app. That way, as long as you read at least one paragraph you won't break your reading streak even when you're too tired and will end up reading multiple pages most days. It's also possible to customize these apps by choosing how many times a week the task has to be done insted of the daily standard option — especially useful if there's always a day in the week with no free time or if your work schedule only leave a specific open window for reading. Consistency over quantity always.

Having said that, it's not useful at all to join challenges if you don't really want to complete them. They have to motivate you, not be a burden (see tip 4). Remember: commit to the reading habit, not a book or a challenge.