Why wasn't stall removed, it's a bad ability
I took out abilities that had no in game effect (like Illuminate or Run Away), abilities that were coded for certain Pokemon (Multitype or Flower Gift), duplicates (Mold Breaker stayed while Teravolt/Turboblaze got cut), and some that were too crippling (Truant and Defeatist). I left Stall because it has some usefulness like powering up certain moves (Avalanche and co.) and pairs well with Zoom Lens. I know it's not much, though.
Why are some abilities bolded
I bolded abilities that had been recently changed. This group of bolds were previously running Flower Gift, which I learned is coded only for Cherrim, so I wanted to highlight their new abilities.
And now Entei can either quad-resist fire and ice, or resist fire slightly less (3/4x effective) and get a water immunity (but hurt by sun lol), while Nuzleaf got two flamin' abilities
That is the mystery of the random number generator feature. You never know what it's gonna do! o.0
Plus Simple Double-Dancer Groudon
He takes some setup but once he gets going, BAM!
Also a many of the Drought users are good pokemon
Drought and Drizzle are the better weathers in Wonkymons since Hail and Sand have bad users. Hydreigon likes the boost to Fire Blast while Porygon2, Shuckle, and Lampent are probably the only other viable mons that run it.