《One》是韩国民谣女歌手李秀英（이지연）演唱的一首歌曲。同时，此曲也是游戏《RF Online》的主题曲。
《RF Online》是一款由韩国CCR公司开发，广东数据通信于2005年12月15日运营的网络游戏。游戏讲述了玩家扮演的三大种族（阿克雷提亚、贝尔托、克拉）之间的反目与对立，以及和神秘病毒斗争的故事。
One歌词：
When I saw you for the first time
I knew you were the one
You didn't say a word to me
But love was in the air
Then you held my hand
Pulled me into your world
From then on my life
Has changed for me
Now I'll never feel lonely again
Coz you are in my life
Love
How can I explain to you
The way I feel inside when I think of you
I thank you for everything that you showed me
Don't you ever forget that I love you
Love I know that someday real soon
You'll be right next to me
Holding me so tight
So I will always be yours
Although we can't be together now
Remember I am here for you
And I know you're there for me
Whenever I want to be with you
I just close my eyes and pretend you're near
I see you I touch you I feel you like real
Nothing can ever change what I feel inside
How long must I be far away from you
I don't know dear but I know we are one
挥着翅膀的女孩钢琴谱 容祖儿 遇到爱用力爱仍信真爱
最初的梦想钢琴谱 范玮琪-多渴望懂的人给些温暖借个肩膀
遗书钢琴谱-蔡健雅-放过自己
生僻字钢琴谱-陈柯宇-抖音终于火了一首正能量音乐作品
恶作剧钢琴谱 王蓝茵-风温柔的侵袭 也许会飘来好消息
那一天钢琴谱 杨坤-带着想你的日夜期盼
Love Story钢琴谱 LYn 愁眉弯唇悉数为你从此眉间心上再无一人
领悟钢琴谱 辛晓琪-我们也终于领悟-你曾经是我的全部
我们不一样钢琴谱-大壮-很不一样
风再起时钢琴谱-张国荣
Surfboard Boogie钢琴谱-Martha Mier
Because He Lives钢琴谱-Bill Gloria Gaither
Bad Apple钢琴谱-ZUN
Pied Piper钢琴谱-防弹少年团 BTS
一笑江湖钢琴谱-闻人听书
记忆深处钢琴谱-朴正元
如果能在一起钢琴谱-梁静茹
Suspirium钢琴谱-Thom Yorke
Pink White钢琴谱-Frank Ocean
英雄落幕钢琴谱-燃烧的音符
轻漪的节音钢琴谱-HOYO-MiX
迷宫钢琴谱-七朵花
Green Hill Zone钢琴谱-中村正人
Benedictus钢琴谱-Karl Jenkins