My question is are these cards valuable to have? From doing more reading I've seen mixed --> positive reviews. Some stating certain cards are too powerful. I've also seen concerns about another group (BCL or something?) also making cards on their own which in my opinion which make things difficult as I would need my play group to also buy into those or only allow one custom set of cards.
Welcome to the game blackhalo23
And gratz on acquiring most of the official cards! I'm not sure why Jungles of Nectavus is so hard to find as there were better warpacks than that particular one in the last cycle, but maybe they did a diminished print run with Jungles, I dunno.
Anyway, back in the day when the game was cancelled the then-most prominent members of the Conquest community (world champions, podcast hosts and other long-time content creators) decided to continue making new content in the form of expansion packs made up of fan-designed cards, which were to undergo a lengthy play-test before release. One of the members behind this initiative already ran an online tournament called the Black Crusade League (or BCL). They decided to use that already-popular name for their cards and group.
Then, out of the blue, a Chinese player or group announced that he too would be making fan-made cards. He created a profile on this site with the name of Team Apoka and started posting card designs, announcing tournament kits and promising a lot of expansions (which he has certainly delivered too.) It turned out Apoka had a professional game designer onboard (which quite shows in a lot of their designs imo) and as such the output pace was staggering, whereas the BCL members focused on giving their ideas a lot of play-testing before publishing cards which slowed down their output considerably by comparison.
This rather sudden new situation caused a schism within the community, as you can well imagine, with many members siding with one or the other fan-design group.
Most regrettably indeed for the community as a whole, things got very ugly and in the end the BCL group decided it simply wasn't worth their time and effort with all the abuse and scheming about on social media. I'm not on social media myself, so I don't know for sure what happened, but never mind that now.
Now there is only Apoka fan-made content (as far as I know) though by all accounts they have moved to Facebook.
We still play the game in Copenhagen (with cards) but we play official cards only. Personally, I don't use Apoka's cards. They are quite well designed, most of them at least, and the skill of their professional game designer is quite apparent, which is nice, but imho they just don't feel like Conquest. Maybe it's due to the new mechanics they've invented, maybe it's in the different wording on their cards. (Different to officially made Conquest that is.) But personally I don't feel as though these cards belong in 'genuine' Conquest and the Traxis sector.
This is of course merely my personal opinion - as a player who have played the game almost since its inception - but for you as a new player that might be quite a different story
Anyway, welcome indeed to the glorious Traxis sector - hope you have loads of fun here!