You can directly upload GPS traces:

https://www.openstreetmap.org/traces

That won't get them into the OpenStreetMap database, but it makes them available (if you set them to public) for anyone looking to add the trails.

There's also apps like StreetComplete. It has 'challenges', where it prompts you for answers to questions and updates OpenStreetMap accordingly (so what is the surface type of a road, things like that).

Vespucci is a full featured editor for Android.

OSM discourages adding raw GPS tracks to the map, rather they should only be uploaded to a sort of waiting room hosted on OSM's infrastructure. A GPS track from a phone or unit is something that needs to be carefully examined, compared to other GPS tracks from the region or aerial imagery, and then tweaked and refined. You need to be able to use specialized mapping software properly in order to contribute tracks to OSM. The good news is that the barrier to entry is fairly low for people like you and me on this "news for nerds" site.

There is bunch of suggestions on how to contribute to OSM with your mobile here: https://learnosm.org/en/mobile-mapping/

On the left side you have a list of apps/devices with guides and summaries

Street complete (fdroid/playstore or GH) is a very easy way to use your phone to quickly to edits or validate data. https://github.com/streetcomplete/StreetComplete

You can also add details using https://wiki.openstreetmap.org/wiki/StreetComplete, it's super simple and almost like a game :)

I quite like that interactive website that helps visitors choose a mapping tool: https://whatosm.pavie.info/

It asks the difficulty level, time you'd like to spend, and whether you want to map at home or on the terrain.

You should be aware that it rather biased (doesn't show tools that are in competition to those that the author was involved in), and out of date.

That could be, but it's a start, and helped me discover a few tools.

Do you have a list of such tools? Do you have a source for attributing this to malice rather than ignorance?

Now, my personal opinion on mobile editing: Vespucci is a bit complex, but basically allows you to do anything on the go. I ususally save GPX tracks using OSMAnd, but it can be heavy on the battery.

After registering, it took me only like an hour to have my track up and mapping it with their brilliant online editing tool. There are some gotchas, but the interface is really friendly and their wiki is vast with info, references and tutorials alike.

Interesting thought.

I have GPS traces for a number of Amtrak routes across America. I wonder if those would be useful.

I imagine something as large as a railway is already covered (especially with the railfan community). In fact in most locations they actually include the number of tracks, passing loops and other features that a simple GPS track will not have.

Why not? It is always informative to have more information. Especially if you know ahead of time, what side of the train to be on, to see more interesting things. Also having information on one map program is great. Why switch apps? Especially since OSM is so privacy friendly.