Here's the partial list from
http://www.pcij.org/blog/?p=1466
TEAM Unity
Joker Arroyo, incumbent senator
Ralph Recto, incumbent senator
Edgardo Angara, incumbent senator
Vicente Sotto III, former senator
Tessie Aquino-Oreta, former senator
Michael Defensor, presidential chief of staff
Juan Miguel Zubiri, representative, 3rd district Bukidnon
Prospero Pichay, representative, 1st district, Surigao del Sur
Luis “Chavit” Singson, governor, Ilocos
Vic Magsaysay, governor, Zambales (view a recent PCIJ blog post on the governor)
Jericho Petilla, governor, Leyte
Jamalul Kiram III, said to be an heir to the Sultanate of Sulu
The Grand Coalition
Panfilo Lacson, incumbent senator
Anna Dominique Coseteng, former senator
Loren Legarda, former senator
John Osmeña, former senator
Antonio Trillanes IV, detained Navy Lt. SG of the Magdalo group
Francis Escudero, representative, 1st district Sorsogon
Alan Peter Cayetano, representative, Pateros-Taguig
Benigno Aquino III, representative, 2nd district Tarlac
Aquilino Pimentel III, lawyer and son of Sen. Nene Pimentel
Sonia Roco, early education specialist and wife of the late Sen. Raul Roco
Guest candidates of the opposition:
Manuel Villar, incumbent Senate president
Francis Pangilinan, incumbent senator
Meanwhile, the Kilusang Bagong Lipunan is also fielding candidates for the senatorial contest, including lawyer Oliver Lozano.