I am probably wrong on this but the first thing that comes to mind when someone asks for a recipe that involves a tenderloin and a crockpot is that it was given to them, they have no experience cooking venison, they have reservations about cooking it, and they probably only have one package of it. If this is the case then make the most of it. What makes the tenderloin the Holy Grail is that anyone can take it and throw it on a grill with minumum or any spices at all, cook it to a medium rare or maybe at most a medium (you want it to bleed when you cut into it), and it will be tender and delicious and have absolutely no gameyness to it at all. You can cook it exactly the way you would cook a beef fillet.
If I am wrong and you have tons of backstrips in the freezer and you are just experimenting, then have at it. If it turns out disgusting and you can't eat it, throw it out and try again.
Here is a crockpot recipe.
Throw the venison in the crockpot with a can of cream of onion soup and maybe a couple of onions cut into large pieces. Cook it on low for 4 or 5 hours, then throw in some carrots and potatos and cook a few hours more.
If you want to take a chance, try grilling. If you have a whole backstrip/tenderloin, don't cut it up. Throw some cajun spices on it, throw it on the grill, and cook it to a medium rare, pull it off the grill and let it rest for 5 minutes. Slice it thin. If you want to be adventurous and impress your significant other, look up a dijon/white wine cream sauce recipe online, drizzel that over the tenderloin, serve with pan fried little red potatoes, a salad, a nice bottle of red wine, and maybe some crusty bread. For presentation, you overlay the venison slices and then drizzel the sauce. If you aren't into the white wine sauce, you could go with a burgandy mushroom sauce instead
If it is pre-sliced, you can do the same except you have to be careful not to overcook and you can't slice it thin.
If you want you can wrap it in bacon to give it a smokey/bacony flavor. Bacon makes everything taste better.
If you are not into the fancy stuff, I also like to cut it into chunks, season it with some taco seasoning and sear it in a cast iron skillet. Again, don't overcook. Try not to eat it all before using it. You can use it to make soft tacos, hard tacos, or burritos with your favorite toppings. I don't use tenderloin/backstrips for this recipe very often. I butcher my own deer and I don't do steaks either. I do roasts, chunks, and burger. Chunks are just big chunks of meat that I can cut into smaller pieces for things like this recipe and things like stir fry which is another good option.