I think those are generally called "
Feedbags" or "
Stembags". Bikepacking.com
has a small review roundup and even a
MYOBG.
I have little experience with them as I use a rando bag and saddlebags but I have positive experiences with Roadrunner bags.
Roadrunnerbags has the
Auto pilot,
Co-pilot or matching
waterproof lids.
I do wonder if they are not too large though and hanging too low.