There are many Mustachian tools around the web.
NetWorthIQ is one of my favorites. It tracks your net worth. And that's it.
https://www.networthiq.com/It will send you a once/month email reminder to update if you like (I have a reoccurring appointment set up on my Google Calendar for it instead).
You can compare across other users of the site (data is aggregated anonymously) based on criteria such as age, geographic location, education level, etc., but take it with a grain of salt. You have to keep in mind that they don't have a large enough sample, and - more importantly - they have a self selected sample of people tracking their net worth. Likely people choosing to use a website like that (who are more conscious of their net worth) will be higher than the actual average.
I find it good just for tracking my own.
And yes, excel can do the same thing, and I do indeed use Excel to track my net worth as well (mainly because I can make it do a best fit line to write a projection equation for my future net worth), but for many this simple tool may be all they need.
I have no affiliation with this website, other than being a satisfied user.
Enjoy!