This includes the 80 main set commons (87%), the 10 common dual lands (10.9%), and the 2 borderless commons (2.1%)
Discounting activated abilities of of lands you control by 1 is pretty significant and makes cards like Nykthos, Shrine to Nyx (currently ruining lives in Pioneer in a mono-green deck, coincidentally) and Cabal Coffers that much easier to abuse
This is one of those cards that is dangerous enough that your opponent has to get rid of it, but annoying to have to spend removal on a 2 drop
Importantly, that colorless part is painless
Your own search criteria for spell options will vary, but having some sort of identifiable purpose when browsing at this stage of EDH creation helps avoid burnout
Ready to Let Loose is Amethyst/Ruby, and could well be the best Lorcana starter deck to date