It's a minefield !
For a rough idea of how I now see it after at least 15 years of using flavours.The first on maggots was Red Zing!by Geoff Kemp.
Summer: Tench Carp Bream Fishy or fruity flavours
Barbel: Spicy,Fishy or Meat(liver)summer or winter
River Carp:Summer anything, winter fruit.
Chub anything but Garlic seems to do better in winter on hemp/maggots. Fishy or fruity on bread mash with crust.
Roach stillwater Autumn/winter essential oils , Aniseed , fruit . Spicy in very cold water. No idea about summer.
River Roach. Fishy or savoury ie cheese in winter no idea about summer.
Perch Spicy / worm flavours in winter.
The following have remained constants in the old flavours draw.
Richworth : Esterberry. tutti fruitti.Liver &Marine , Aniseed, Blue Cheese. All in spray or dip form.
Hutchie Monster Crab.
Nash Jamaican Spice Essential Oil.Roach attractor , Bream attractor.
Nutrabaits.Betain.Geranium essential oil.N butric acid
Whizzo worm extract.
Braddock Supaspice
Garam Masala from the local deli.
Finally molasses from the local farm shop.It is the cheapest and best!.