4chan? It doesn't touch the scale and breadth of Reddit and I was always a little uncomfortable the handful of times I visited. Maybe because of no-rules /b/ but there are definitely some wholesome boards out there.
Any specific boards you would recommend on 4chan? Are there any other image boards worth using with reasonable discussions?
It's really up to your interests, but I'll say /news/ because that's what I used Reddit for mostly. Here's a handy list: https://wiki.bibanon.org/4chan_Boards