>>53989562I could defend most of them.
>Pichu, Cleffa, and Igglybuff were definitely made for marketing; all three having mascot status during Gen 1 such as pic related>Togepi was to show the concept of Pokémon Eggs>Tyrogue linked Hitmonlee and Hitmonchan together to an evolution line>Smoochum, Elekid, Magby, Wynaut, and the Gen 4 babies are as you said, being early game versions of their evolutions if allowed to be obtained at that point in the gameAzurill I question, but I assume it's for the same reason as Pichu, Cleffa, and Igglybuff and the mizutama pun.
I also question Mantyke not so much for Mantyke itself, but why Mantine's counterpart Skarmory lacks a pre-evolution.
Also Little Cup is neat and I will defend its existence.
The biggest mistake made with pre-evolutions were requiring incense to obtain them via breeding, which has finally been fixed. Maybe next gen we'll see more after this change.