Which anime (or other) did these characters come from?

The first one: from the heart of an angel, a humanoid computer.

The second one: from the novel Duel Doll? Does "white and silver" mean the "Nadeshiko color" of the wheels? 》

The third picture: from "Meng Mei Girl"

Picture 4: From Guarding Sweetheart.

The fifth picture: Ling Xian travels to Hollyleaf (レィセン? うどんげいん? ィナバ(reisen udongein inaba) A character in the Oriental series of fan games, the moon rabbit who fled from the moon to the eternal pavilion. The appearance is a long-haired girl with rabbit ears, wearing a uniform suit and tie. As can be seen from the vertical painting of the defeated copy of Yongye, she is wearing a white blouse. Hua doesn't wear a suit outside, but she wants to wear a short-sleeved shirt in the sky. It first appeared in Oriental Night Copy.

The sixth painting: from bianco El dorado, this is a group of てぃんくるMeng paintings.

The seventh picture: the comic "Chocolate and Vanilla"

The eighth picture: White Night Tea Party Painting Collection: てぃんくるは

The ninth picture: from the original painting collection of h2so4 painters.

Picture 10: From Destiny's Sky

Part 11: From the animation "Prism Ark".

The twelfth picture: from the painting collection [Cat Works] NEKO SOCKs is the work of sayori, a domestic painter.

The thirteenth picture: it's the head picture drawn by the OMC team. OMC is an organization that specializes in drawing portraits for people.

Picture 15: From Guarding Sweetheart.