What are the number of points needed for Levels from challenges/ badges?

Yes, you are right, in the JSON definition, the limit is there, not in the Marathon badge description, though (at least not in the original English version).

As for the list of runs of certain distance, you can do it with the search filter on the Activities page:

Actually it's also in English, but in the earned tab and below the main description: "You've earned this badge X times. Limit 250." It's for Marathon, Ultra 50k, Halloween, New Year, Valentine.

I have also one Ultra 50mi and 60/30 Day Goal Getter and those have other text: "You earned this badge on X." without displayed limit.

So maybe you need to earn at least 2 same badges to see limit there.

And yes, you can search on the Activities pages, but it's just easier to click on a badge. Other option would be to move list of activities by distance to the Records' page. They could even just add search links with distance filters pre-set. Though, list of activities under badge seems nicer.

BunBun! said:

They could even just add search links with distance filters pre-set.

You can simply bookmark them, but I am sure you know it. I do not think it is really necessary to abuse the badges for that purpose, or creating an additional functionality for it:

https://connect.garmin.com/modern/activities?activityType=running&minDistance=42000&maxDistance=45000 

The badge system, in it's current state, is a de-motiving, discouraging, flawed gamification mechanic. This could be fixed easily by keeping the same ratio/percentages between current levels, but inflating by a factor of 10x. This means that the current level 10 would be level 100, and this would create a more achievable sense of progression by adding 10 smaller goal posts between each current level. If it takes 2-3 years to go up one level, it is no longer something that will generate motivation and will ultimately be ignored. The current system drops motivation around level 5.

1337638 said:

The current system drops motivation levels around level 5.

I find it OK. I do not need to get a new level each month. I am kept motivated sufficiently even just by seeing the points incrementing practically daily, and watching the gap to the next level closing more and more. In contrary, it would be demotivating if it was as easy as at the beginning. It must be a challenge, not a routine!

The levels aren't really needed at all. The points in itself is the only thing needed. 

I got 1117 points now (level 6) which places me as #16 amongst my connections. Next person got 1156 points. I'm trying to beat my connections. I got connections in all levels including level 9 and 10. My biggest problem is that most of my connections are crazy badge collectors that take all badges every month so it is hard to beat them.

There is also a motivator in taking all badges. Currently I got 32 badges that I can take. Some are pretty easy like this months challenge badges. Some are harder since they require that I start with scuba diving...and wingsuit flying...which actually is easy to fix but it requires that I travel to a indoor wingsuit center.

Do you still have badges you can take or are you all done?

:-D

The solution for improving gamification should not be "just don't use it". That is unhelpful and unproductive. If you don't find gamification motivating in general, you should avoid commenting. Also, badges for non-activity events and non-progress are a bit patronizing and dilutes the entire reward quality. This stuff is all gamification 101 these days. Garmin's system is out of date and has a terrible scaling system. Get from level 1 to level 4 by "commenting on a posts" and buying crappy starwars watches, but then get to level 5 by spending 2 years of your life accepting monthly challenges and exploiting friend challenges. All of this is easily fixable and would help more people during the 1-3 year adoption period.

The badges concept is a game that you basically play with yourself.
Yes, some of the badges you can get early on in the first year and don't mean much to some of us, but the system is setup for all,

I'm about halfway thru level 4 since I started a little over a year ago. I don't go for badges by changiing my country or location. I take only those I see in GCW. I take every Walking, Hiking, Cycling challenge that is available every month, and along the way I have picked up other related badges like Climb badges for Cycling, etc. I don't really care if it is 500, 1000, or 10,000 poiints between badge levels. It is the challange and beating it that counts for me and the virtual badge is nice to see.

And yes, the Cycling Tour these past 5 months is getting harder and harder to motivate myself to do.

BTW I'm 80 and I use the challenges as motivation to push myself to do more. So Cheers to Garmin for making that available!