Elite Four on Pokemon Silver

Answer 1

The Elite Four in Pokemon Silver has these members with their Pokemon:

Will

He has Psychic-type Pokemon, which are Xatu, Jynx, Exeggutor, Slowbro, and another Xatu. Bringing a Fire, Ghost, Dark, or Bug-type Pokemon will easily knock them out, except for his two Xatu.

Koga

He was a Poison-type Gym Leader in the Kanto region, but has made his way up in the Elite Four in Johto. He has Poison-type Pokemon like mentioned before. He has a Ariados, Venomoth, Forretress, Muk, and Crobat. Since most of them know Toxic, bring a Steel-type Pokemon to avoid being affected by the poison status. Skarmory will be a good choice, since it has Flying-type moves that can get rid of Ariados and Venomoth. Bring a Fire-type to get rid of his Forretress. (Bug/Steel type)

Bruno

This Elite Four member is a master at Fighting-types, but he has a sneaky Onix. Bruno has a Hitmontop, Hitmonlee, Hitmonchan, Onix, and Machamp. Flying-types may seem like a good choice, but Hitmonchan has Thunderpunch and Rock Slide. You easily make the Fighting-type Pokemon faint by bringing a Psychic-type, but with Onix a quick Surf will do the trick.

Karen

Although she is great with Dark-types, she also has 2 Pokemon that aren't Dark. She has Umbreon, Vileplume, Gengar, Murkrow, and Houndoom. A Fighting-type will be able to hit Umbreon and Houndoom, but will have a hard time with Vileplume and Gengar. I'd bring a Pokemon that has a Fire-type move, Psychic for Gengar, and Electric for Murkrow.

Last, but not least:

Champion Lance

This Dragon-type trainer has encountered you a few times during the game, but this is now your chance to prove your strength againt him. Watch out, though. He has a Gyarados, 3 Dragonite with different movesets (Thunder, Blizzard, and Fire Blast), Aerodactyl, and a Charizard. It is pretty easy to check that you'd need a Dragon-type move or a Ice-type move. (It will do 4x the damage if Ice on a Dragonite) Charizard and Aerodactyl can be taken down with a Water-type move, and Gyarados can be taken out by an Electric-type in a hit.