For myself, I would only use one soft plastic minnow I pour in a few sizes on 1/16 oz or 1/32 oz jigheads. I've caught crappie on the following, but not as consistently:
small crank baits/ jerk baits
hair jigs
beetle spin
Mepps type spinners
spoons (Swedish Pimple and Acme)
Grub-worm hybrids (fused with a candle flame)
slim 3.5" worm with minnow tail
small Pop R
Variety is nice, but I prefer consistency when the bite is slow and when lure versatility is essential (fast-medium-slow, shallow-deep).
Remember what the Beatles said:
All you need are jigs.
All you need are jigs.
All you need are jigs, jigs.
Jigs are all you need.