I've been searching for ages for a "one stop" news forum on up coming releases and I have had no luck.
What I do now, is subscribe to dedicated YouTube channels related to Anime statues / figures, but I also regularly check AmiAmi and Solrisjapan - I mean, you're probably going to buy from them anyway

so why not.
There's probably other premium sellers out there, but this is my strategy for keeping up with what's coming.
On a side note, both these stores sell pre-owned figures as well. So if you missed a figure and want to get it, this is a better alternative to eBay, as you can more or less guarantee the authenticity of a figure from AmiAmi.