I am actually of a split mind on the matter.
I have stories I want absolute control over because I have a rough of at least key moments planned out. At the same time I have settings those stories take place in that I would love to do collaborative on since I will never touch every detail/facet of that setting and would like to see love given to things I will never personaly get to. Then there is the fact I have a lot of half finished material I would sorta be interested in seeing what other people can make of.
Mostly I do fantasy or SciFi. I have a fairly hard ‘no’ on romance or faith based. I mean I guess I could but it wouldn’t be those weepy teary put faith in god and suddenly everything is peachy type stories. Those to me are boring and unrealistic and send a message of ‘they got a happy ending but you won’t because you are not deserving enough.’
OK sorry. SciFi. Case in point my two personal favorite settings are a setting where robots exist in a world where humanity is either dead or confined to sleeper vaults (haven’t decided but leaning on humanity is gone since once humanity shows back up robots abandon building their own civ, which is boring.) My other favorite is where a civ that had 22nd century level technology backed and augmented by magic (think ‘weaving’ from wheel of time mixed with ‘bending’ from Last Airbender) was in a global war, is just now building up to where citystates are forming and people are at a steampunkish level of technology combined with scavenging old things… And dealing with the fact necromancy is illegal because that entire branch of magic got blamed for the war when the main character has an affinity for said illegal magic (and is both not emo, an in a stable relationship.)