In a bit more detail:
Yui's chosen avatar looks like she's 8-11 years old. She was Kirito and Asuna's adopted daughter, and for the brief time where she had admin access, was overpowered as hell. See previous page for a Lil' more detail.
Silica was 12 years old at the start of SAO. Her "dragon pet" was a member of the species called Feathered Dragons. Pina, the dragon, about the size of Silica's skull and could fly, attack, and heal.
Silica later joined Kirito's harem. It's exactly as creepy as it sounds.
Lisbeth started forging Kirito's weapons after he casually broke several of the weapons in her shop. Because, Y'know, the author of SAO enjoyed making Kirito a blatantly overpowered one man army.
Asuna, like most of the others, would've been more interesting if Kirito hadn't wandered in and sucked all the depth from her. She was a front-line (the top tier players, basically) DPS specializing in rapid hits and dodging pretty much everything. Also a great cook. Reduced to waifuness when Kirito came along.
EDIT: Forgot Argo. IIRC, she's one of the only memorable characters in all of SAO who wasn't sucked in by the black hole Gary Stu known as Kirito. Famous for being pretty much the best information broker in SAO, she also compiled a (free) guide for new players when the death game nature of SAO was revealed.
In the beta, Argo chose to keep the red whiskers (makeup) given for an in-progress quest. When SAO started, she chose to imitate the whiskers with makeup until she could get the permanent marks from the quest.
TL;DR: SAO would've been so much better if Kirito didn't exist or was written
way differently.