I would argue that there are a few ways this phrase can be inverted:
No rights reserved
Implies that the author waives all rights to his/her work (i.e. ultimately places it in the public domain)
All rights included
I've seen this one in the context of royalty-free music being used in the commercial sense, where if you pay for the license, you can use that song anytime anywhere, with all rights to the song. This seems to be the opposite of "All rights reserved" which we should know by now what it means
Copyleft
While not really a phrase, it is the opposite of copyright itself. Used primarily in software but maybe some other media can also be considered copyleft. As far as I'm aware, it has some ties with copyright itself (that you cannot remove attribution from the author, and, in case of software, must distribute it as is, without putting any restrictions yourself)
There are probably more means other than what I've listed, and I would love to hear your thoughts and suggestions!
I'm a big fan of WTFPL, myself.
I'd like to disrespectfully disagree, it's a trainwreck of a license and while I get the memeing, some people actually go ahead and use it seriously, just because they can't be bothered to put some thought into how their software should be treated, that doesn't protect neither themselves nor the users
It's all fun and games, until you need a warranty disclaimer.
WTFPL is my favorite license