Hidden Giveaways

I think if you know the name, you can search for it?

As far as I know - no there is no way to do that.
If you remember part of the name, you can search for the game.

If it helps, you can turn off the manual filter if you're sure the giveaway is somewhere you'd come across again (assuming you'd recognize it). That's the only other solution I can think of other than scanning through the pages and pages of hidden games.

You could try searching for the game you wanted to hide, maybe you're in luck and you hid DLC or the complete version of the game you were trying to hide.

ctrl+F and search for the word "hours ago" or "days", you will find which one you hid pretty fast since most of them have been hidden "months ago" I assume. p.s. you can enable endless scroll with some scripts and scroll all the way down so that the search was among all pages and then search like I said.

If you have hidden the game recently, you could check your browser history.