《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
还是我钢琴谱 韦礼安-还是会不知所措 没有我你会不会寂寞
安娜的橱窗钢琴谱-封茗囧菌-橱窗里的木偶
遇萤钢琴谱 橙光音乐 / CRITTY 倒转流年只为那一眼红颜
夜之光钢琴谱-花姐-我走过夜夜夜的黑做的梦梦梦最真
一荤一素钢琴谱-毛不易-你给我港湾，我给你期盼
丑八怪钢琴谱-薛之谦-最美的丑八怪
那片海钢琴谱-韩红｜30年后与初恋同唱那片海，一笑释当年
宠爱钢琴谱-TFBOYS 极尽宠爱
那么骄傲钢琴谱 金海心-别那么骄傲，我随时都会走掉
暖暖钢琴谱-梁静茹｜爱一个人希望他过更好
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
Benedictus钢琴谱-Karl Jenkins
Everything Stays钢琴谱-Rebecca Sugar
Green Hill Zone钢琴谱-中村正人
I Like You So Much Youll Know It钢琴谱-Ysabelle Cuevas