One site comes to my mind is Ico drops_[1], don't know why, maybe it's memorable name. I'm not an active nor expert investor regarding ICO project, but sometimes found some good projects worth to be studied further. However, you can't expect to get hidden gems if you don't do your research, read or watch some reviews on several websites and youtube. You can check https://medium.com/@henryw1990/top-10-ico-rating-and-reviews-websites-ff0be69890b6 to see some potential projects.
[1] https://icodrops.com/bounty-list/
[2] https://icobountyhunt.com/