Something that I use all the time, and something that I feel fits in to Lusternia!
ta
Untargetted -
1st Person: You offer a faint smile and a gentle wave before turning away as you chirp a cheerful, "Ta!"
3rd Person: Waving her fingers and offering a faint smile as she turns away, Tremula chirps a cheerful, "Ta!"
Targetted -
1st Person: Giving Iosai a faint smile, you wave at her before turning away and quipping a cheerful, "Ta!"
2nd Person: Tremula flashes a faint smile at you before waving and turning away, quipping a cherful, "Ta!"
3rd Person: With a wave and a faint smile, Tremula turns away before giving Iosai a cheerful, "Ta!"
Not sure if anyone else would use it, but it's one that I do all the time (to the point where I have aliases set for certain people I use it with).