Various series I've read or am reading and would recommend to others. 
Bias towards likable well-written main characters, assertive/charismatic male protagonists, harems especially with polygamy.

Ignore the order, not going to sort them.

Series not on Novel Updates;
- Sasaki to Pii-chan; Fun. A clusterf*ck of cliches and genres (aliens, demons, magical girls, espers, isekai, monsters, secret organizations), similar to 'A Certain Magical Index'. Technically a harem, but sadly unlikely to ever have any romance (Protagonist treats them like daughters).

- Otherside Picnic; It's 'Roadside Picnic'/'STALKER' with a side of yuri. The main characters venture into another world full dangerous supernatural anomalies, searching for a missing person and to make some cash by selling supernatural artifacts. The main characters are well written and there's slow yuri romance. Also has manga adaptation

Also check my other list: https://www.novelupdates.info/viewlist/110239/