In Pokémon Trading Card Game for the Gameboy Color, you earn packs when you defeat opponents. There are four types of booster packs:
I want to find the most effective way to earn each of these packs in the post-game so that I can have a complete collection of cards.
The general strategy I remember when I played decades ago was to seek out Imakuni - defeating him grants one of each pack and he is fairly easy to defeat. However, after looking at an All Cards speedrun strategy for the game, it seems like packs are typically weighted towards a certain type:
So, most packs you get from trainers in this game are preferenced towards a certain type. Like, if you need an Electabuzz, it's waaaay more likely to have it as your rare card if you duel an Electric type trainer that gives Colosseum packs.
They go on to say that Imakuni's packs are weighted towards trainer cards and are thus less valuable:
Imakuni is a very very fast way to get boosters, but they're Trainer preferenced, NOT typeless. So, they're not as useful as they could be. Basically, once you have 2 sets 'completed' (i.e. you know you can get the remaining rares/uncommons for those from the mailbox), Imakuni is really only giving you 2 packs, the same as a normal trainer battle. If you have every Trainer rare in those remaining sets, then you should grind off someone else, so you can be getting 2 typeless packs instead of 2 trainer-pref packs.
I have almost all of the trainer cards after a casual playthrough, so I don't think it makes sense for me to continue fighting against Imakuni.
The guide goes on to suggest a strategy for getting Laboratory packs and grass rares from Evolution packs:
Generally, Evolution and Laboratory are the sets that will still need some grinding done. I like to grind off of Kristin for Evolution packs (as I'm almost always missing multiple Grass rares) and Nikki for Laboratory packs. Fighting them with Magmar-only is faster than fighting Imakuni with Zapdos, and faster than most other matchups in the game. (Stephanie, who gives Laboratory Psychic packs, is absolute hell and should never be fought imo, even if you're missing all 4 Lab Psychic rares.)
However, this strategy seems specific to speedrunning the game and eventually involves exploiting the boosters from the mailbox system to get missing cards.
What's a general strategy to obtain booster packs towards completing a collection during a casual playthrough?