Getting a hang of Clip Studio. I could do this for everyone with their signature Pokemon if they so please. Would let me fill my files.
If you don't mind doing Lucy with her Purrloin or Lynette with her Cofagrigus, that would be amazingly awesome of you. If you just wanna do one, go for Lynnettes please.
Not so sure Purrloin will be Lucy's 'signature pokemon' later, but hey, you never get rid of your starter.