ooh, some of these look interesting! I'll warn that I'm not so much into playing, like, super hypermasculine characters as mains... that said, they might be a bit flamboyant, but that doesn't mean they're not more than willing to be the dominant one ;) 

In particular I have quite a good character if you're into anything piratey... I definitely like the idea of a pirate and a noble of some sort. I have a few potential ideas for that, but the core of it would most likely be that your character was on a ship that was attacked by pirates and taken hostage/for ransom. My character could either be the captain of said ship, or else could just be one of the crew mates who perhaps ends up taking a fondness to the prisoner. This could work in historical settings, though because in his original version the character is sort of a merfolk/fish person, fantasy is also great for him, and I [i]slightly[/i] prefer him that way.

If you like vampires or demons, I also definitely have a lot of plot ideas for those concepts, but I didn't see mention of either in your post so I'll refrain from outlining them for the time being haha.

Finally, I also do like the shapeshifter plot, #5. It's honestly pretty good as it is, so I don't really have any tweaks to suggest for that.