I love a spicy boil, like them plain too, but prefer spice. Most any will work. We don't add in other foods with the spicy boil, usually. But to a couple packets of the boil mix, I always add 2-3 cups apple cider vinegar, powdered all spice, powdered cinnamon and cayenne pepper, 3-4-5 tsp or so of each. Occasionally we add red pepper flakes/seeds and often powered cloves, if more spice is desired. I have a big pot and usually have about 3 gallons of water (sea water or salted the same).
Our most popular boil mix is just good old pickling spice, with the additions above, we dump a bunch in, a cup or more. If you have a smaller pot, scale accordingly, but better to have too much me thinks... We remove the vein just before cooking, bring water to a boil, dump them all in, bring back to a boil, cool and enjoy. If you really like spice, try this, use strainer to remove about 1/2 of them out of the pot. Leave the rest to soak, as the boil cools, it will pull more spice into the meat. You can actually dump in more vinegar in as it cools and leave it for a long time. Tasty.
The boil works great with Crab too. The only different thing we do with crab, is after 10 -12 minutes of boiling, quickly remove and layer ice, crab, ice, crab, ice... to cool quickly, keeps it very moist and tender. We do leave a few crab to soak as the boil cools, dump in more vinegar and water to start it cooling. Never done the ice deal with crawdads, they have a very different meat, little lobsters. Yum...I need to go crabbing soon.