mostly phychic types like Abra
there are many MANY Pokemon that can use the hm flash in Pokemon sapphire. the following Pokemon can: grovile( treeko),kirlia(ralts)shroomish, eletrike, Roselia, plusle, munun, magnemite, voltorb and many more
When a Pokemon has the move Flash, you go into Party, then select the Pokemon with Flash using the 'A' button and there should be an option that says "Flash". It is only usable in dark locations or within battle.
Nincada is a fantastic Pokemon to use these moves on. Not only can it learn Flash and Rock Smash, but also Cut, Dig, and Secret Power which are all moves that are required later on.
the best pokemon to use is mudkip.
the second gym leader gives you the right to use it and you can find it at one the caves if i remember right. (in dewford town)
ditto
any fire Pokemon and some leaf Pokemon but you shoulb be able to find a Pokemon near the cave youre going in
use their Pokemon
how do you use flash? just go to pokemon and go to the pokemon that knows flash. press A and it will say in blue text "Flash" select that and it will use Flash. it's very useful in dark caves.
There is no place to buy elixers in Pokemon Sapphire. You can, however, use your Itemfinder to search them out randomly.
You can use the Good Rod in Pokemon Sapphire to catch Pokemon. To get it, talk to a fisherman on Route 118.
There is only one pokemon you can use it on and that is eevee to get vaporeon