This is my personal favourite genre. I love it so much. It is difficult to find EunHae abo fics so I've written all of the ones that I've found and read and loved.

HaeHyuk:

1. Unavoidable Mate by SLHusky

2. Where I belong by FirstAnotherSujufan

3. Mutually beneficial by FirstAnotherSujufan

4. Falling together by FirstAnotherSujufan

5. My Incompetent Alpha by FirstAnotherSujufan

6. The one time Idiocy is a blessing by ReapJewelFish

7. MoonChild by crime-tsumi

8. The Zeta by FireFeerie

9. The World Of HaeHyuk Marriage by arcee_bee 

HyukHae:

1. Fate's Trick is Love by Leesofthae

2. Howl in the Night by luna2moonPanda2Koala

3.Howling at the Moon by Starlight66

4. Love Story by HyukjaesJellyBean

5. The Couple Counselling by Sikakira

6. Our Long Love's Day by Catskilt

7. You who was sent to me by moonchant  [ One of the best (if not THE best) abo ffs ever written. It has everything you would want in an abo fic and more; such a gem of a ff that I'm glad I found and could read.]

HyukHae + HaeHyuk (both)

1. Turn Up The Heat by haekass 

2. Howlin' for You by haekass 

CAT

1. I'm not your cat by gnagna_onni ( highly recommended)

2. In love with Kittens by cottonplushie

3. My new... (boy) friend by gn