That's not an oxymoron! While the whole point of being 'indie' is to be independent (primarily of a publisher!) there are many other ways a publisher can help you while letting you remain independent. Traditionally game publishers would pay an upfront fee that paid for a studio to develop their game, but in return own all of the IP and almost all of the revenue from a game (and sequels!!).
Nowadays with digital distribution one of the main reasons to need a traditional publisher is gone but there are other things they can help with like PR, advertising and marketing budgets around launch, getting you onto marketplaces like Steam, etc. Sometimes this could be more of a partnership than a publishing deal.
I've just started talks with a few indie-friendly publishers for Guild of Dungeoneering so I thought I would share my list for others considering this approach. Some of these are full-on publishers with a focus on indie games, some are actual indie developers who also publish other dev's games, and some are marketing specialists.
- Indie Fund - http://indie-fund.com
- Devolver Digital - http://www.devolverdigital.com
- Double Fine Presents - http://www.doublefine.com
- Paradox Interactive - https://www.paradoxplaza.com
- Team 17 - http://www.team17.com
- Midnight City - http://www.midnight-city.com
- Adult Swim - http://games.adultswim.com
- Curve Digital - http://www.curve-studios.com
- Chucklefish - http://www.chucklefish.org
- Finji - http://www.finjigames.com
- Versus Evil - http://vsevil.net
- nkidu - http://www.nkidu.com
- Reverb - http://reverbinc.com/triplexp
- Mastertronic - http://www.mastertronic.com
- Positech - http://positech.co.uk
- Square Enix Collective - http://collective.square-enix.com
- Surprise Attack – http://surpriseattackgames.com
- Headup Games - http://www.headupgames.com
- Wadjet Eye Games - http://www.wadjeteyegames.com
- tinyBuild Games - http://tinybuild.com
- Digital Tribe Games - http://digitaltribegames.com/
- Evolve PR - http://www.evolve-pr.com
- STEAKSTEAK - http://steaksteak.com
- Whippering - http://whippering.com/
- Indie Wolverine - http://indiewolverine.com/
I'm focused primarily on PC, as is most of the above list, but if you are looking for help with a mobile game I'd recommend looking through this twitter list as quite a few of the list are mobile-focused.
Thanks to the Indie Game Developers facebook group, @kristruitt, @LukeD and /r/gamedev for helping me put this list together. If you have any suggestions to add to this list feel free to leave a comment!