How long you got? I really hope this thread takes off because you could write volumes on this topic.
Generally, I break my lure/bait usage into three categories based on what I'm hired to catch.
Beaver
Canine
All Other
The first is obvious and really only has lure and no bait. The lure is either castor or food based. I like to keep two castor based.
Backbreaker for my main with WCS beaver blaster or
Beaver Plus as my secondary change up. The secondary use is where I trial new lures. My food based is the incomparable
Woodchipper and is always used in conjunction with an actual bait of peeled sticks, beavers choice of what they are currently cutting on site. I'm open to trying other food based.
This next is where my lure bag gets FUBAR but I'm trying to boil it down to just a few tried and true. First the bait, there's lots of good ones available and IMO just about anything edible will grab a canines attention. I've used a ton of different homebrew baits over the years from fresh killed squirrel to cracklins to fresh melon. The advantage of prepared baits is the stabilizers and preservatives that keep them "fresh" for a longer period plus a few lure type additives that increase appeal. Currently I'm pretty much sold on three that I like to keep in the bag Hiawatha Valley, Predator Plus and Widowmaker.
As for lures I'm trying to simplify and avoid buying everything that catches my eye. (They're called lures for a reason, lol) I want a good gland lure for each species coyote, red and grey fox plus a couple curiousity/food types. And no bag is complete without a skunky call type. Since I have yet to really pare down my list ill just list some I use and trust.
Dobbins RdFx is my go to gland lure for reds and general all purpose canine lure.. I also like his Digr. Violator 7 is an excellent coyote gland lure. Old Grey Buzzard from Dobbins will always have a place in my bag. Generally I prefer a paste type lure but June's Windwalker or whatever he's renamed it is as good as it gets in a liquid type. For skunky I like GHII or Voodoo.