I always think of Derelict as the next chapter in FreeSpace, then the Sync-Transcend duet (Even if command never hears about it
) then your choice of either Inferno/Blue Planet style Solgate stuff..
Gag.
Derelict and Blue Planet, with seemingly organic Shivan Lucifers that regenerate? They're Shivans, not Shadows.
Sync and Transcend? Who's storylines are about as FAR from FS2 as you can get? Yeah, people enjoy them, but Freespace? Don't think so. I believe Ransom even maintains that they're an alternate universe.
The best post-capella campaign I've played that's captured the feel of the actual games is Procryon Insurgency, bar none.
The whole ancients not dead thing was a little questionable however.
That's not to say that other campaigns aren't FUN and worth playing over and over but, as stories or campaigns which fit into Freespace? Not so much imo. Even my own campaign, what there is of it is a pile of crap, pirates out the ying yang. Bunch of irrelevant pilot chatter. Not at all like the proper games.
If you pick up FS1 and play it, then play FS2 you can be like "wow, these are Freespace." But pick up most 3rd party campaigns, and it's like "wow, that was fun, but . . . very very different from Freespace".