Bulbapedia has this information, though it is not all accessible on one article.
On their articles for each area, all of the Pokemon trainers in the area are included, along with information about the Pokemon they have. For example, here's the article for Kanto Route 1, which includes all of the trainers in that specific area for each Pokemon game the area is in.
Bulbapedia also has the article on Pokemon Trainers in general. In the list of trainer classes section, all of the trainer classes in each game are listed, and there are links to the page for that specific trainer class, which includes a list of all of the trainers of that class for each game, as well as what Pokemon they have and their levels. The area each trainer appears is not directly included on these pages, however, if you click on the name of the trainer, it will take you to Bulbapedia's article for the area they appear in.
TL;DR: This list of trainer classes from Bulbapedia should help
