If there's someone who was on another show (ex. Martin Stein, Wally West) rate them according to how they were on The Flash, not on the other show. Also in the case of "Harrison Wells" (Thawne) and "Jay Garrick" (Zolomon) rate them based on their facade, not on the character they actually were.
Here's mine:
Barry Allen
Cisco Ramon
Caitlin Snow / (Killer) Frost
Ralph Dibny
Harry Wells
H.R Wells
Joe West
Martin Stein
Ronnie Raymond
Sherloque Wells
Wally West
Cecile Horton
Eddie Thawne
Julian Albert
Chester P. Runk
"Harrison Wells" (Eobard Thawne)
Nash Wells
Nora West-Allen
Jesse Wells
"Jay Garrick" (Hunter Zolomon)
Kamila Hwang
Tracy Brand
Iris West-Allen
Allegra Garcia
Chester, Allegra, and Tracy could've been higher but we haven't seen that much of them. Also, I put them as one, but you can put Caitlin and Frost as separate characters.