What can you suave negroes tell me about event flags in gen 1?

Going for the complete pokedex (yellow), but I'm fairly alone in the world and won't have anyone to trade with. Need doubles of Eevee, the alternate fossil, alternate martial arts pokemon, etc.

Is there any documentation about resetting these events in your save file, scooping up each version of your prize, and then marching onward? I see that it's an obvious feature of PkHex, but there's strangely little about it written on their forums.

Also are there any other utilities which have similar functions? I'd be curious about playing around with the 'events' of the game, and it looks like PKHex's users are the only ones who call these 'flags' - what term should I be searching for here?

Resetting gyms, legendary meetings, even things like the voltorbs in the electric plant...

anyway thanks for reading and I hope you all have a good day and a safe place to sleep