>>50644750>post elite fourby technicallity, HGSS. But even if we take after Red, HGSS has one of the most (Safari Zone, Battle Frontier, many legendary sidequests, lots of rematches)
Emerald is similar but the Safari Zone is less expansive
ORAS brings a good revamp to Secret Bases and cool online functionnalities but no BF removes it from being a contender
BW2 has quite a bit too (World Tournament, White Treehollow, lots of little sidequests all over the region)
I guess next on the list is SWSH w/DLC? But that's only due to the base game campaign being... so empty, lacking of any side content.