Here is a list of the best Ecchi / Harem animes that i have watched
1-High school dxd
2-High school of the dead
3-Infinite stratos
4-Trinity seven
5-Absolute duo
6-Saijaku muhai no bahamut
7-Rakudai kishi no cavalry
8-Rokudenashi majutsu
9-Date a live
10-To love-ru
What about you ?