For the Adobe breach specifically, you might try the site set up by Last Pass, which checks your email against the breached data: https://lastpass.com/adobe/

The added feature is that, if your email is in the list, Last Pass will share with you how many others had your same password -- and the list of all password hints associated with that password. If more than a handful of others used the same password, that should jog your memory about which you used.

P.S. I'm not associated with Last Pass and actually use a different product. But I found this site very helpful.

You can just torrent users.tar.gz (the leaked list of encrypted passwords) and then grep the file for your email address, which will give you the encrypted version of your password.