This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Tactics Ogre
The scene and subsequent Villainous Breakdown where Vyce is blamed for the assassination of Duke Ronwey...and hanged.
Denam finding out he wasn't Walister but Bakram (his ethnic enemy) from his father...who was nearly tortured to death and dies in his arms.
Picking the wrong options when Denam was talking to Catiua and watching as she stabbed herself right in front of Denam.
In the neutral path, Gildas dies and is reanimated by Nybeth
In general, how little Nybeth cares for his son Dievold and daughter Oelias.
If you think that’s bad, he’s indirectly responsible for their deaths in one of the new scenarios for the PSP remake. Also, the man even tries to kill his other daughter Cressida once she’s had enough of the family business.
Accidentally letting Cerya die...right in front of Cistina.
Letting Folcurt die on the way of saving Cistina. She just tried acting like it's all right, but you KNOW she's pretty sad about the whole thing.
Finding a broken and desperate Sherri in Balmamusa.
Finding out the canonical ending in its Prequel-Gaiden GameKnight of Lodis was the ending where Rictor is possessed by Shaher and then killed by Alphonse, then when he faced Shaher, Eleanor grabbed onto Shaher's hands when he was dying and died with him...thus sending Alphonse back to Lodis to have his name changed to Lanselot Tartaros...and then raid Denam's home village. The ending where Cybil' Eleanor's older sister, dies with Shaher and Alphonse and Eleanor are never heard from again after they elope was preferable.
Accidentally continuing the path where Catiua commits suicide in front of Denam and then watching as Denam, the new ruler of Valeria, is assassinated by a gunner.
Even if you manage to avert the latter by gaining the approval of the three clans, Lodis is preparing to launch a full scale invasion of Valeria.
It's not advisable that you take the chaos path in the PSP Version...if you grew attached to Ravness. She always refuses the Duke's plan no matter what. IN the Chaos route, Vyce kills her right there after her Galgastani heritage is revealed.
Some of the death quotes make you think My God, What Have I Done?. Such as for example, someone wants revenge because you killed her husband in another battle. Then she says she's pregnant as you kill her.
The PSP version has a wizard you fight in chapter two who wants to kill you because after all, you killed his twin brother.
The Warren Report also has info on quite a lot of the generic commanders that you kill. For example, the aforementioned wizard and brother were a philosopher and a professor.
Lanselot Hamilton's music box that his wife gave him, which the now wheel-chair bound knight tries to reach for after Lanselot Tartaros had completely broken his mind and body after months of torture.
Not to mention what happened to Lanselot Tartaros in the Gaiden Game, which takes before Tactics Ogre. Losing the ones he cares for changed him from a wild-eyed idealist to a bitter cynic we see in Tactics Ogre.
Going into a certain path or failing to recruit a character generally has them ending up in a horrible fate in a cutscene. One example would be Ozma's, where she winds up in a vegetative state.
Leonar's death in the Chaos route, even more so in the PSP remake because there is an extra dialogue if you brought Arycelle with you, which makes it hurt more because this would be the last time they speak and it's each berating the other for their choice of side. And right after he revealed Ronwey's plan to align with the Dark Knights and before dying, he declared that he still loved Arycelle before dying. Damn it.
The second time you fight alongside Azelstan, and his not-quite-adoptive daughter is killed from offscreen.