Rias: 

Akeno: 

Asia: 

Koneko: 

Isami: (female Issei) 

Xenovia: 

Irina: 

Rossweisse: 

Raynare: 

Kalawarna: 

Mittelt: 

Grayfia: 

Valia: (female Vali) 

Kuroka: 

Le Fay: 

Ophis: 

Sona: 

Tsubaki: 

Serafall: 

Sona's Peerage: (except Saji) 

Ravel: 

Riser's Peerage: 

Yasaka: 

Tiamat: 

Venelana: 

Gabriel:

Murayama:

Katase: 

Kunou: 

Seekvaria:  

Viser: 

Ingvild:  

Latia: 

Kushina: 

Coriana: 

Aika:  

Jeanne: 

Roygun: 

Lint: 

Nyx: 

That's the DxD harem done. There are a few crossovers for this book that I would like to add. Such as Fairy Tail, Testament of Sister New Devil, Eminence of Shadow, and one crossover or two  crossovers of your choosing. 

If you have any harem members from them, let me know at the comments below, peace out and enjoy!