Pokémon has come a long way since the original 151-Pokémon line-up. Many of those who started as stand-alone Pokémon acquired evolutions, pre-evolutions, and even mega-evolutions in later generations. However, there are still a few that remain standing alone.
It has been confirmed that Gen One's Farfetch'd is finally receiving an evolutionary form (Sirfetch'd) in Pokémon's upcoming Switch games Sword and Shield. That leaves only three original Pokémon without evolutionary counterparts; Ditto, Tauros, and Lapras.
Ditto
Ditto almost received an evolution all the way back in Gen Two's Pokémon Gold. In a demo of the 1997 title that was recently leaked, there is evidence of Ditto evolving by way of an evolutionary item; Metal Coat. The idea of this copy-cat Pokémon evolving may seem like a moot point as it just transforms into whatever Pokémon it's battling. But, an intriguing notion has been brought to light that, possibly, the evolved form would be able to transform into the evolution of its opponent instead. That would certainly shake things up! Unfortunately, the evolution was ultimately scrapped- probably because it wound up resembling a crude form of Domo.
For a while, people also believed that Meltan, first introduced in Pokémon GO, was a Ditto evolution - this turned out to be untrue.
Tauros
Tauros was also expected to gain an evolution in Pokémon Black and White. That evolution was to be Bouffalant. This makes total sense as both Pokémon embody two almost interchangeable real-life species; a Bison and Buffalo. What doesn't make as much sense, but is widely accepted by the fan base is the correlation between Tauros and Miltank. The Pokédex lumps the two together, merely because they are of the bovine persuasion, both normal-type Pokémon, and share similar biomes. Bouffalant hits all of these checkmarks as well and maintains a closer resemblance to Tauros. Both Tauros and Bouffalant represent untamed species, while Miltank represents a highly domesticated one. The creators may have been going for the chance to create another pre-evolution with the ability to evolve into multiple Pokémon - though we never saw that either - given that Tauros are all males and Miltanks all females. While some will say Miltank is the female counterpart to Tauros - a sort of Nidoking/Nidoqueen relation- Others are still aghast over this missed opportunity to see Tauros have a proper evolution.
Lapras
Possibly the most anticipated of all to receive a possible evolution would be Lapras; the ever helpful, sea-dwelling Pokémon. Unlike the previous two, no one has heard more than a whisper about a Lapras evolution. That is until Pokémon Sword and Shield. Now, with the games' newest feature leak, Gigantamaxing, it looks like Lapras will - if not a true evolution - at least be obtaining a regional form in the Pokémon world's newest region, 'Galar'; similar to Alolan forms.
Lapras' Gigantamax form is said to not only take on a gigantic size, but also dawn new layers and musical notes on its shell as well. Whether it is only a new Galarian form or a full-fledged evolution, Pokémon fans will surely be excited to see what's in store for this long-time favorite in the upcoming Sword and Shield.
It is still unclear what the future holds in Sword and Shield for these three original Pokémon. But, with Farfetch'd's evolution Sirfetch'd finally confirmed as Sword's exclusive Pokémon, it's only fitting to speculate which one of these classic Pokémon might earn an exclusive evolution for Shield!