By finding multiple skins, do you mean you're looking for a specific skins in your skins folder, or are you trying to look for skins that other players have used? The
Skinning subforum has a list of skins other users have created and are working on that can be downloaded with a simple click, but if you're looking for top player exclusive skins —
osuskins is a great place to look as there's just about every top player's skin listed on there for you to preview and download.
There's also
https://osuskinner.com/ where you can create your own skin with unique customization, including an option to change the "play-skip" (skip button) you were asking about when a song is starting up. You can also download a base template (the default osu! skin that comes with the client) to mess around with from the website and place your own or other skin elements in if the elements listed on the website aren't to your liking, but the preference is all up to you ^^