Raven taking on Nevar (finally) at the finale of The Secret Temple.
Raven's outburst at Ervan and the Feral Children when he finds them locking up his warriors is equal parts this and Nightmare Fuel. In fact, whenever Raven gets screentime in The Dragon's Eye which isn't just exposition, he's generally being pretty badass.
The final episode has Raven not only getting his Staff of Power back after Ervan had stolen it a few episodes earlier, but also managing to resist being corrupted by the Dragon's Eye long enough to destroy it.
Satyarani, standing up to a group of demons that were threatening the warriors in The Secret Temple. And mocking Nevar.
The fact that 3 warriors (Corso, Delra, and Tanel) managed to win The Island, making this first spin-off the only time that there were multiple winners in a series.
Normal Raven series
Arnor being the only warrior to win Demon Square during her qualifying week in series 5.
Other warriors who did this were Ramso in series 6, Anmah and Sonos in weeks two and three of series 7 respectively, Sarpes in week 3 of series 8, and Reggos in week 1 of series 9.
Any time a warrior with a fear of heights conquers that fear such as Kinia in series 2.
Wenra, who had only one hand, made it to the final week in series 4 before being eliminated. The only reason he came sixth was due to another awesome moment; namely, Kinsa beating Way of the Warrior.
Melka in Series 6 completing Spider's Wood on her own after her teammates were taken via accidentally touching the webbing.
While it was a Foregone Conclusion for some that Sarjed would win Series 10, the fact that throughout the whole final week she did not fall out of first place is still pretty impressive.
She also managed to hit three bullseyes in Warrior's Eye.
Kyson being the only warrior to succeed in High Rope in week three of Series 5.
Tezan was also the only warrior to successfully complete High Rope in week three of series 6.
Beron being the only warrior to succeed in crossing The Chasm under the Blasted Mountain in Series 7 (in the only series that The Chasm was in).
Pargan completing Demon River on day 5 of week 1 in Series 8. Especially since she was the only one to do so that week.
Yalbec and Reggos completing Conundrum, one of the most difficult mental challenges, in week 1 of series 9. Bonus points for them being the first warriors to ever attempt it since it was introduced in that series.
Japul and Nosson winning the same challenge in week 3 with only seconds to spare.
Series 1 has Sejen, who gets to come back on day 5 of week 1 due to Gaale's Non-Gameplay Elimination and manages to get herself into first place by the final challenge, Riddle of the Portal. Sadly she did not make it through to the final week but the fact that she had grown in confidence enough since the beginning of the heat to the point that she was able to get to third place in that round is still great.
Volna completing Snake Pit on his own in Series 4 after his teammates both accidentally stepped into the pit. Unlike with Melka completing Spider's Wood, Snake Pit was a race between 2 teams making Volna's win just as memorable and awesome.
One from the Gaelic version of the newer Raven format: Hathlow, Onia, and Tamgar beating Demon Army, marking the first time that the challenge had been completed under said newer Raven format.
For that matter, Tamgar becoming the first boy to win a regular Raven series in a little over a decade since the last time a regular series had a male winner was when Versad won series 7.
For the Wrestler:
Ending the decade long undefeated streak of "Dr. Death" Steve Williams in the US in 1997, with a little help from his stable "Raven's Nest".
Holding the WWE Hardcore Title a massive 27 times, the second most reigns of anyone.
Practically any time that he was on the mic in his ECW days. There's a reason Raven is known as one of the best promo guys in wrestling.
On a 1999 edition of WCW Thunder, Eric Bischoff publicly announced that anyone who didn't like the way the show was going could leave, singling out Raven and Konnan. Raven for his part got up, asked for his released and went right back to ECW.
Winning the NWA World Heavyweight title in TNA.
For the Comic Character:
Re-empowering Darkseid in Our Worlds At War, and leaving the God of Evil completely confused as to what Raven is.
Defeating Phobia in her white outfit days and giving her a brief HeelFace Turn.