I'm going to add Evan Williams, Black Label or Bottled in Bond (I prefer Bottled in Bond but it is a little higher proof at 100). This is going to be in the same realm as Elijah Craig, same distillery (Heaven Hill). Old Forester is a good one, they have a few different distinct offerings. I love Wild Turkey 101, it's an interesting one because it's a cheap standard "get you drunk mixer" but also generally considered the best affordable bourbon by experts. There's so much to explore, 50mls are great for trying the stuff that comes in that size, bars help with the rest but also just buying a sh!t load of bottles will get the job done
