Shining spears were added before '97, and I assume their bikes are special and passed down just like their armour ( at least thats what the special paint job implies). Thats really what I meant by miss counted, you forgot shining spears but remembered warp spiders, both added in the same codex.
These four are probably the most well known, and popular. I would personally add Saim-Hann to the list for a 5th... but i'm not entirely sure if they are the most important to add. I usually make a rule not to bring up Rogue Trader... But... Which Craftworlds were in Rogue Trader, besides the 4 mentioned here? Anything else with a'lot of history? I bring it up because our newsletter hits very soon.
Lugannath a Craftworld from Rogue trader Victims of Nurgle very anti chaos but overall not much is known which would give the staff of EC a lot of flex when it comes to the games fluff and filler.
I would say Ulthwé is Ultramarines of the Eldar. Samm-Hann to me is more like Imperial Fist. Very well liked and popular but not the poster-child for the group.
Well if true that for 5th and 6th edition at least Saim-Hann is always in the cover and that one showing up for most items in the store. Back in 3rd and 4th It was Biel-Tan, and I think in the first editions it was Alaitoc. So it actually varies a lot between edition, as opposed to SM who always seem to have Ultramarines as their poster boys.