This is a bit odd... it's the IP that EC is based on, not the main TT iteration specifically or what sub-company of GW who makes the models... All Forge-world Items are part of the IP and all are avalible to us used as part of the IP.
Technically all support craft would be from FW...
But anyway what I would want to see is one of these:
The Tyranid Hierophant Bio Titan

Yeah its apart of the IP so it should/would be in

ForgeWorld have a lot of fraction customized gear. Would be great to see it in the game, but i think it will not bi on the launch.
At first standart gear needs to be added.

I think once the game have a very large armored boot in the door they will be unable to resist the pull of forge world simply because they produce some amazing models and allow one to get way more costomization.

I'd love to see this as a late tier unlock for those who dedicate themselves more to being a transport driver.

This thing can carry up to 25 Marines inside its hull, and is bigger than a Land Raider I could see it having a lot of use as slow but sturdy transport to drop a ton of troops into a front line that needs reinforcing.

if it gets me those awsome beakie helmets yes

My Fire Prism can use a quick 26 kills.

Totally

You'll probably see them added as micro transaction cosmetics.

In different campaigns - different units and tech. I hope that in some battles we will gona see even Titans (someday after lunch=)