While this is not a standalone work (an AoT doujinshi, rather), it is still fabulous and deserves all the recognition it has gotten. It shows sides to characters that we never imagined them having in these sorts of scenarios. The story brings a dark twist to traditional Omegaverse, and branches off into uncharted territories that many A/B/O doujins are afraid to explore.
Shingeki no Kyojin dj - Mihitsu no Koi ni Yoru Ai