We keep a list of some applications and other things over here too: https://awesome.ipfs.io/
I'd argue eternum is not quite at the same level since it just takes an IPFS object as an input (but no IPFS output). Op made a thing that takes an IPFS object as an input and produces a different IPFS object as an output.
There are certainly many IPFS-based apps.
I'd say IPFessay (https://gitlab.com/stavros/IPFessay) is much closer to an IPFS-based API, since it can run entirely on IPFS with no outside servers.
We keep a list of some applications and other things over here too: https://awesome.ipfs.io/