18 drivers so far announced for F1 2013, leaving just 6 seats still to be officially confirmed, assuming HRT continues...

Confirmed 2013 F1 drivers:

Sebastian VettelGermanyRed Bull-Renault
(Confirmed for 2013 and 2014, but there are performance clauses)Mark WebberAustraliaRed Bull-Renault
(Deal expires at end of 2013)

Fernando AlonsoSpainFerrari-Ferrari
(Confirmed for 2013, with options for 2014 and beyond?)Felipe MassaBrazilFerrari-Ferrari
(Deal expires at end of 2013)

Jenson ButtonBritainMcLaren-Mercedes
(Signed 'multi-year deal' in October 2011)Sergio PerezMexicoMcLaren-Mercedes
(Signed 'multi-year deal' in October 2012)

Kimi RaikkonenFinlandLotus-Renault
(Signed two year deal in November 2011, second year was an option)

Lewis HamiltonBritainMercedes-Mercedes
(Deal expires at end of 2015)Nico RosbergGermanyMercedes-Mercedes
(Signed 'multi-year deal' in November 2011)

Nico HulkenbergGermanySauber-Ferrari
(Signed deal for 2013, contract length not announced)Esteban GutierrezMexicoSauber-Ferrari
(Signed deal for 2013, contract length not announced)Robin FrijnsNetherlands Sauber-Ferrari
(Signed test and reserve driver deal for 2013)

Pastor MaldonadoVenezuelaWilliams-Renault
(Signed deal for 2013, contract length not announced)Valtteri Bottas FinlandWilliams-Renault
(Signed deal for 2013, contract length not announced)

Daniel RicciardoAustraliaToro Rosso-Ferrari
(Signed deal for 2013, contract length not announced)Jean-Eric VergneFranceToro Rosso-Ferrari
(Signed deal for 2013, contract length not announced)

Charles PicFrenchCaterham-Renault
(Signed 'multi-year deal' in November 2012)

Timo GlockGermanyMarussia-Cosworth
(Signed new 'long term deal' in July 2011)

Pedro de la RosaSpainHRT-Cosworth
(Deal expires at end of 2013, although future of team is currently uncertain)

Michael Schumacher GermanyRetirement

Likely candidates for remaining seats...

Romain GrosjeanFrenchLotus-Renault

Paul di RestaBritainForce India-MercedesJules BianchiFrenchForce India-MercedesAdrian SutilGerman Force India-Mercedes

Max ChiltonBritainMarussia-Cosworth

Heikki KovalainenFinlandCaterham-RenaultVitaly PetrovRussiaCaterham-RenaultRubens BarrichelloBrazilCaterham-Renault

Narain KarthikeyanIndiaHRT-Cosworth

Jaime AlguersuariSpainIn talks with 'several midfield teams'Kamui KobayashiJapanFuture unknownBruno SennaBrazilFuture unknown