Rejunivation Hardware (online) or check out your local Habitat For Humanity Restore.

Check out Carmeon Hamilton on Instagram/ or her blog. She just refreshed her kitchen and used knobs that look very similar.

Not sure if this is it...

https://www.etsy.com/listing/848473533/mid-century-modern-concave-disk-round?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=mid+century+knobs&ref=sr_gallery-1-35&col=1

I found lots of knobs with a curved concave profile (search for "round dish knob"), but none with the V profile.

I second the referral to Rejuvenation. If these cannot be matched, I would consider a mix of these and complimentary brass handle pulls, allocated to uppers, lowers, and drawers appropriately. This would look more intentional than mismatched, but similar dish knobs.

An option for non matching but almost would be Rejuvenation dish knobs with a backplate for the base (or tops) and originals for the other.

(Warning: I used Rejuvenation's dish knobs in chrome for a previous remodel and the lower ones kept getting loose. Apparently toddlers do not like to see their image upside down and WILL try to correct them. Good knobs!)

Amerock also carries a dish knob. Much cheaper. Neither is quite the same as your original.

Thanks, everyone, for your advice! So appreciated!