I've recently been replaying Silver, and using a few different Pokes to what I'd normally go through the game with, with surprisingly good results.
 
Exeggcute was brilliant for me, just because I had a Red cartridge to hand. You get him just after Bugsy's gym, and he's already got Hypnosis, which is invaluable. Annoyingly, without R/B, you can't evolve him until late into Kanto, but if you do have access to a first gen game, you can just trade him over as early as Ecruteak, give him a Leaf Stone and a Psychic TM and watch him OHKO everything for ages.
 
Mareep replaced my starter as 'most reliable Poke'. Two great moves in the punches, despite not getting much else why do you need anything else? Massive special attack lets you pummel most things hard.
 
Eevee was a burden, until I got traded the Water Stone. Suddenly, wow. Massive special attack, takes hits relatively well, and a STAB Surf to round it all off. Admittedly, bar that it doesn't get much (Icy Wind, lol. Also got a RBY Blizzard TM) but when that's killing anything that doesn't resist it, you don't really need much else, to be honest.
 
Used Sudowoodo for a bit, but he really didn't help much, at all. After getting him, admittedly he's a bit of help in the Ghost gym (Not as much as everything else though) but after that he gets murdered in the Lighthouse, in the sea crossing over to the island, in the Fighting gym, in Jasmine's gym, and by that stage he's woefully underlevelled and had to be dropped.