i have probably read every 40k crossover fanfic on this site most are good a few are really good and rest are usually terrible.

but most have one thing in common it usually involves a space marine or a small group of space marines or imperial guardsmen ending up on equestria.

some dont have any space marines or guardsmen at all but instead have another 40k faction appear usually chaos or orks and i have enjoyed reading almost every single one.

but theres one 40k crossover i have always wanted to see but has not to my knowledge been written and that would be having one of the primarchs end up on equestria.

it could be written in anyway such as maybe one of the primarchs infant pods ends up crashing on equestria instead of there original home world or maybe one of the loyal or pre daemon prince traitor primarchs crash lands on equestria after a massive space battle.

or the one i would most like to see done is after being killed by Horus on his flagship Sanguinius wakes up on equestria still wounded from his fight with Horus and finding himself not on Terra but badly wounded on an unknown alien world in a strange forest (which turns out to be the everfree) with no idea how he got there where he is then discovered by one of the ponies maybe fluttershy or zecora.

upon seeing how badly injured he is the pony tries to help him and since sanguinius is probaly the most kind hearted and non violent primarch doesn't immediately  kill the strange horse xenos on sight and the story continues from there and at some point rainbow dash challenges him to a race that i would like to see.

so if anybody reads this and would like to write a fanfic like this or knows another writer who would you would have my eternal gratitude and it would make for an incredibly awesome fanfic