Usagi Tsukino is the central protagonist and namesake of Sailor Moon.
There are barefoot shots of the Inner Senshi in Naoko Takeuchi's Sailor Moon Art books. Naoko originally wanted to make the Sailor Senshi barefoot, but scrapped the idea at the last minute.
A close-up of her is shown as she is getting out of the bathtub at the beginning of episode 4 (3 in the dub) in the original series.
Her feet are seen as she is wrestling her brother in a Hot Spring.
Sailor Moon R
In "Naughty and Nice" she is shown barefoot in PJs when she discovers that Mini Moon wet her bed while sleeping with her.
Sailor Moon S
In Sailor Moon S episode 10 "Mixed Emotions/The Kindness of a Man! Yuichiro, Heartbroken by Rei?" her feet are seen while poking fun at the relationship of Rei and Yuichiro. She rubs them together while with Luna.
Sailor Moon Super S
"Hardships of A Warriors! Sailor Senshi's Night of Destiny"
"Hell Demon Battle! Love Will Prevail"
"Love and Moon Power! The End of The Nightmare"
Sailor Moon Crystal
Usagi's piggy toes were showing