The Staryu/Starmie evolution chain is nothing special. It learns a decent number of moves but nothing that will stand out from the rest of the water Pokémon pack. If you choose to catch a Staryu, your best bet is to get rid of its default moveset, except for its water-based moves, and teach it others through HMs and TMs. As always, wait until Staryu has learned the majority of its moves before evolving to Starmie.
Mr. Mime is an OK Psychic Pokémon that will suffice until you can get a heavy hitter, such as Alakazam or Mewtwo, in your arsenal. Mr. Mime will have to be taught the best attacks that Psychic Pokémon have to offer, such as Psybeam and Psywave, because its default move list is quite lacking. Confusion is great for inflicting that status ailment in early battles, but later it’s not going to hold for very long against stronger opponents.
Scyther should be better than it is in Generation I Red/Blue. Its move list is highly disappointing and the number of decent moves it can learn through TMs and HMs is low. It learns no Flying moves despite being a dual type and it does not and cannot learn Bug -type moves, what little there are, despite being a Bug-type Pokémon. This is remedied later in more current generations but the lack of moves makes Scyther a non-choice.
Jynx is an interesting Pokémon. It is a combination Pokémon that incorporates moves from three different types: Ice, Normal and Ghost. It is also capable of learning moves from the Fighting, Water, Psychic and Poison movesets through TMs. Jynx is one of the few Ice-type Pokémon and thus its advantages immediately make it worth a look. Given its array of learnable moves, you could take a Jynx very far and wreak havoc with little downside.
Electabuzz is an excellent Pokémon to have as the Electric anchor on an Elite Four-bound team. Its default moveset is great with few weak moves and it can learn a variety of moves from the Fighting and Psychic movesets without the disadvantage of being a dual-type Pokémon.
Magmar is a great Fire-type addition to your team that’s in need of a fire Pokémon anchor. Fire Pokémon are a precious commodity, especially if you didn’t start with Charizard’s evolution chain. Magmar has a good moveset, can learn quite a few moves through TMs and HMs, and is strong enough to handle an Elite Four battle easily once it’s leveled properly. Also, finding a Magmar later in the game will ensure you’re ready to handle using a tough Pokémon type like Fire.
Pinsir is an average Pokémon, much like its fellow Bug, Scyther. Like Scyther, Pinsir should be better than it is. It’s also disappointing in that it never learns Bug-type moves. The two advantages that Pinsir has are that it’s a pure Bug type, avoiding the dual-type weakness; and, it naturally learns Guillotine, a one-hit KO move that has decent accuracy. While it can slightly improve its default moveset, it should be better and there are other Pokémon deserving of a place on an Elite Four-bound team.
Tauros is deceptive in nature. At first glance, it’s a boring Normal-type Pokémon with an average moveset. But with research of what it can learn, Tauros becomes a unique and worthy addition to any team. There is a wide variety of moves that Tauros can be taught through TMs and HMs, and they run the gamut of types. With this wide range of moves and lack of a dual-type weakness, Tauros could potentially be a great anchor for an Elite Four team.