This is a totally unofficial list that I put together myself over on the Glorantha G+ group. So details may be wrong but a lot of this has been officially confirmed (e.g. that the product is planned, though not when it will be released).
I thought I'd share it here, for fun and info.
The Dragonrise, the “offstage” material from The Eleven Lights, for HQG - Ian Cooper
Fonrit setting book for HQG - Ian Cooper