You can and you should contribute - Open Street Map
Today I found out that it's actually a lot easier to contribute to Open Street Map than I thought. There are some serious gaps in house addresses in my area and I was painstakingly using the built in browser editor in the browser.
But, you can use a FOSS app (available on fdroid) called StreetComplete that makes it a lot easier to help out filling in the gaps in your local map data.
It's really fun - kind of like Pokémon Go but you are actually making an impact 😁
This yes, ever since someone mentioned StreetComplete, I have been using it and love it ! Super easy to contribute. The only thing missing is the ability to add nodes. But that I usually do on a computer/ or using Organic Maps android app.