Eve(Black Cat)-created to be a bioweapon and the center of "Eden" and counterpart of "Adam" by Torneo Rudman and Mason, rescued by Train Heartnet and Sven Vollfield
Primula (Shuffle!)-created for the Yggdrasill project by the Netherworld and the Gods' World, rescued (or moreso given to) Rin Tsuchimi
Illyasviel von Einzbern (Fate/stay night)-created as a Lesser Holy Grail to unlock the Great Holy Grail by the Einzbern mage family, rescued (hopefully depending on the ending, need an Illya route!!!) by Shirou Emiya
Len (Kagetsu Tohya)-created by an unnamed mage who defeated Einnashe for use as a basic familiar, makes a new contract, so she can continue to live, with Shiki Tohno
White Len (Melty Blood)-created by Aoko Aozaki for use in general mischief, makes a new contract, so she can continue to live, with Shiki Nanaya (though at first they try to kill each other)
As you can see, not all of them have to scientifically created; some were born via magecraft. Eve, Rimu, and Len all are very quiet (at least at first), which differs from Illya who is very hyper, and White Len is tsundere, aloof and dangerous at first but rather cute and slightly less dangerous, once one gets to know her.
