National Park lists 32 Pokémon across 23 encounter methods (grass (before the national pokédex, bug-catching contest), grass (national pokédex, saturdays, bug-catching contest), grass (national pokédex, thursdays, bug-catching contest), grass (national pokédex, tuesdays, bug-catching contest), and more), between level 7 and 36.
National Park in other guides
The same area in other ROM hacks on this site. Each one has its own encounter table.