Basic recipe:
Cider vinegar as the liquid.
Kosher Salt
Crushed black pepper...lots of it
Crushed coriander seeds...lots of it
Derivatives, using some or all:
Spicy-
Add crushed red pepper flakes
Add spicy dried peppers
Sweet-
Add brown sugar
Asian-
Mirin
Garlic
Star Anise
Chinese 5-spice
Soy Sauce
Sesame oil
Sesame seeds
Flavor enhancement-
Accent MSG
Soak overnight stacked tightly in the liquid. Put them in your biltong box and dry to your preference, remaining careful to not knock off the spices.