This is the Mahjong Key Cap: dot series. They are 1-9 dots that can be mounted on the numbers 1-9 of the keyboard.

（这是麻将键帽：筒牌系列，1-9筒可以安装在键盘的数字1-9上）

I have separated the colors in the 3mf file. If you download the stl file, you need to split it into parts in the slicing software and color it separately.

（我已经在3mf文件里分色，如果下载stl文件，需要你在切片软件里面拆分为零件，分别上色）