Do you want to lean more toward Asian (soy sauce, sesame oil, ginger, etc.) or more classic (olive oil, herbs, garlic, etc.)? Have you had a chance to think about your side dishes?

I use this brine for pork chops, but I think that it would work well for pork tenderloin too. https://food52.com/blog...

8 cups water, 1/2 cup each sugar, kosher salt & black peppercorns.

Hope this wasn't for dinner tonight! :-) I like both of these a lot - very cozy winter dishes.

Honey mustard pork tenderloin
https://food52.com/recipes...

Cider-brined pork with calvados, mustar and thyme
https://food52.com/recipes...

With this...

Todd Coleman's genius potato gratin
https://food52.com/recipes...

Molly Wizenberg's cream-braised cabbage (if you're not doing the Calvados & cream pork)
http://www.bonappetempt...

or any sauteed cabbage

And this...

I've used a "brine" of buttermilk to good effect when I've had buttermilk to use up. It does a great job of tenderizing the meat. I'll just stick pork chops or a tenderloin (or chicken, for that matter) in a Ziploc bag with a few cups of buttermilk (to coat and mostly submerge the meat) and then add either some smashed garlic cloves or garlic powder and either some fresh herbs (I don't even bother chopping them, although I will at least bruise them so that they release more flavor) or just dried paprika or dried mustard and some onion powder if I don't have any fresh herbs lying around.

Not a brine, per se, but one excellent tenderloin mentioned elsewhere - https://food52.com/recipes... The key is not to overcook it. A meat thermometer is essential here. This roast makes great Cubans, too! ;o)