Just to help a little, I'll put a list of the ones I've already seen with a tsundere in it. I'll have a "*" next to ones I liked and a "**" next to ones I loved.
Baka and Test: Summon the Beasts **
Gosick **
Yuru Yuri **
Shakugan no Shana + II **
Ookami-san and Her Seven Companions *
The Familiar of Zero/Zero no Tsukaima
Hayate the Combat Butler/Hayate no Gotoku *
Toradora! *
Angel Beats! ** (You could say Yurippe's a tsundere.)
Clannad + ~After Story~ **
Kanon (2006) **
Pandora Hearts **
Hidan no Aria/Aria the Scarlet Ammo *
InuYasha + Final Act **
Hoshizora e Kakaru Hashi
IS: Infinite Stratos * (Wasn't a fan of the tsunderes in this one, though. Only Charlotte.)
The World God Only Knows + II *
Toaru Kagaku no Railgun *
Toaru Majutsu no Index + II **
Kampfer *
Lucky Star**
Kore wa Zombie Desu ka?/Is This a Zombie?*
Negima! Season 1, 2, OVAs and OADs *
Oreimo *
Ouran High School Host Club *
The Melancholy of Haruhi Suzumiya *
Yokuwakaru Gendaimahou *