Definitely Ricken and Nowi until post-game. Then there's Sumia who somehow always makes it to second/third place every time as well, along with Morgan, so them too.
Chrom used to be on this list so hard simply because unlimited free weapon ... until I crippled him with Chrom/Maiden in a game where the RNG Goddess hated his stats (he had 10 mag... mid-game ...) so nowadays he doesn't even get a medal any more.
Sometimes Lon'qu and Gangrel because Tricksters.