There are a lot of opinions out there regarding coding outside of work and whether it's required for success or not. Personally, I think it's very much up to the individual. I code outside work because I love to code. Still though, after a long day of work sometimes the last thing I want to do is dive into ANOTHER project.
Side projects can be great. They are a great way to learn, to build your skills and to build your portfolio. They can also be overwhelming and time consuming. Sometimes you just have 30 minutes and you want to do something fun and quick.
Some people choose an open source project to contribute to rather than coming up with their own project. I think open source is amazing but it's also a huge commitment. To learn someone else's code base and get up to speed enough to contribute, that takes time. Which is awesome, if you want to spend time investing in it but I just have never found the time or motivation myself. After coding all day in my day job, I just want to do something fun, something quick but challenging that I can complete in one sitting or dip in and out of without pressure.
An alternative I've found is code katas. Code kata's are set problems you can solve using a language of your choice. There are a plethora of katas out there, all varying in difficulty and area of focus. Some focus on algorithms, some on fundamentals and logic. There's something for every mood. Code Wars is a great resource for katas. Another resource I use is reddit daily challenge. They provide challenges of different levels easy, medium or hard. You can also see the solutions in the comments and improve by reading other peoples code. Another way I like to practice is to just pick a cool feature on a website and try to implement it myself. Usually setting a time limit to challenge myself.
All of these little efforts will compound together to help hone and build your skills. You don't necessarily have to have an epic side project or be an open source savant.
The most important thing is to keep learning and keep coding. ✌️