Aperol: Any apertivo, including Lillet, Nonino Apertivo and other aperitif liqueurs (not a bitter)
Green Chartreuse: Dolin Genepy (also, a ratio of 2 to 1 to 1/2 can create a substitute for Chartreuse; Genepy, Strega and Absinthe - let them marry for 2- 4 weeks).
Yellow Chartreuse: Strega Liqueur (some say Yellow Galliano, but does not have enough anise or floral notes.
Campari: Carpano Bitter, Luxardo Bitter, etc.
Fireball: Jim Beam Fire (you can taste the whiskey and has a nice spice level - a better version of Fireball)
Buffalo Trace: Evan Williams 1783 or Elijah Craig
Blanton’s: Four Roses Single Barrel
Eagle Rare: Russell Reserves 10, Bulleit 10 or Knob Creak 9
Disaronno: Lazzaroni Amaretto ( I personally like this one better)
Angostura bitters: Any aromatic bitters, like Fee Brother’s Old Fashioned or Woodford Reserve Spiced Cherry.