I don't know about Lepa Bukva.
Skabrnja: true, that was an atrocity where about 50 Croat civilians were killed by Serb paramilitaries.
Vukovar: Battles between the blockaded JNA and the ZNGs of Tomislav Mercep. There was also the Croatian "Black Legion" and Slavonska Brigada Tigrovi (Slavonian Tiger Brigade). I'm sure the Serbs had their own awful paramilitaries there as well (Arkan? White Eagles?). The Croats perpetrated a lot of intentional atrocities over Serb civilians and POWs early in the siege. After the town fell, Serb paramilitaries perpetrated counteratrocities over Croat civilians. The massacre of 200 at Ovcara, while reprehensible since it was a killing of POWs, was not an execution of civilians. It seems that most of the Ovcara victims were Croatian paramilitaries who, after Vukovar fell, went into Vukovar hospital and put on hospital gowns, pajamas, and casts to appear as if they were patients. This was done in collusion with the Croat nationalist head of the hospital, Vesna Bosanac. It doesn't excuse it, but it does show that it's not quite as it has been portrayed. If you want to see a bit more about the Serb side of Vukovar, search "Vojin Dabic" or "Ksenija Lukic" in Google and a website should come up.
Srebrenica: more complicated than stated in the media. Naser Oric, Muslim commander from 1992-1995, used the "safe haven" (which was supposed to be demilitarized) as a base for launching attacks on Serb villages. He destroyed about 70 Serb villages and killed about 1000 Serb soldiers and civilians (including women and especially elderly). The 1995 deaths of 3000 Muslim men (whether by execution or ambushes as they were fleeing to Tuzla) was a horrific atrocity, but I believe it was inspired by the earlier behavior of the Muslims. It's unfortunate that Srebrenica has been abused by NATO to justify ex-post-facto its behavior, and that more do not know of the earlier events around the enclave, which would set the 1995 atrocity in better context. I don't consider it genocide, though, which is something the NATO/ICTY axis has been pushing.
Sarajevo: the siege was reprehensible, no doubt about it. What people don't discuss is Muslim actions against Serbs in Sarajevo, which included massacres and detention camps (Viktor Bubanj barracks, central prison, etc.). My father's best friend was kidnapped by Sarajevo Muslims in 1992 and killed. It is believed that several thousand Serbs in Sarajevo died in this way. The criminals who did these deeds are Musan Topalovic "Caco," Ramiz Delalic "Celo," Ismet Bajramovic "Celo 2," Jusuf Prazina "Juka," and others. On Mt. Trebevic in Sarajevo is a limestone pit called Kazani in which hundreds of Serbs were dragged off by Caco & co. and liquidated and thrown into the pit. Furthermore, some incidents in Sarajevo were actually staged by the Muslims, such as the Markale and Vase Miskina "massacres." Ballistics analyses indicate that these two events could not have been perpetrated by a Serb projectile, and appear to have been due to explosively planted in the marketplace. The expected reaction by the West (and that's why the Muslims did it) was air strikes on the Bosnian Serbs.
Bleiburg: I have no idea where you came up with this one. Bleiburg was perpetrated mostly by Slovenian Partisans. Political responsibility for the executions lies with Mitja Ribicic and Zdenka Kidric, both of them Slovenes. And the Chetniks were actually among the victims at Bleiburg, since the Partisans treated them just like the Ustase and Belogardejci.
Btw, I don't see you mentioning any Croat deeds in Croatia and Bosnia: Medak, Gospic, Zadar, Pakrac, Osijek, Blijesak, Oluja, etc. in Croatia and Lasva Valley, Mostar, Capljina, Mrkonjic Grad, Orasje, etc. in Bosnia. Perhaps you're a bit biased here, too.
Lot of things could be found on internet these days.
Not biased at all, because each side has their own truth.
Numbers and reports vary depending who collected them, released them, when and where, etc.
Serbs are "always" victims, but have great lobby (probably second best after jews) and diplomation, and that just denies every attempt to prove opposite.