[tchvil]

This one is cheap and light and works great on various bikes but on a 29er:

https://a.aliexpress.com/_Eu2mwYj

[analog31]

Link is broken, but my curiosity is piqued.

[_whiteCaps_]

Link worked for me, the item description is "Rrskit Bicycle Fender Ultra Light Foldable Bicycle Mudguard"