Help?

Go to your library, click "support" at the right of the screen, and then select the option to remove the game from your account.

I tried it but free to play games haven't that option :(

You should be able to remove f2p games on the license page (https://store.steampowered.com/account/licenses/)
Though I have one f2p game I can't seem to remove. It was activated through key, so maybe that's the reason.

Steam seems to be lazy in their upkeep. Some F2P games simply disappear as soon as they are uninstalled, others need fiddling, and still others are a royal pain to make go away. I wish I could offer some help, but I've got nothing. P