I'll make a list here of announcements of games which will also be available on PS4 at the Xbox conference:
- Metro: Exodus gameplay (2018)
- Assassin's Creed: Origins story/gameplay trailer and gameplay (October 27th 2017)
- PlayUnknown's Battleground trailer (timed Xbox One exclusive)
- Deep Rock Galactic trailer (no date, timed Xbox One exclusive)
- The Darwin Project trailer and gameplay (no date, timed Xbox One exclusive)
- Dragonball Fighter Z trailer
- Black Desert trailer (MMORPG, timed Xbox One exclusive)
- The Last Night trailer (timed Xbox One exclusive)
- The Artful Escape trailer (timed Xbox One exclusive)
- CodeVein trailer (2018, timed Xbox One exclusive)
- Tacoma trailer (timed Xbox One exclusive)
- Indie compilation, some probably also on PS4
- Ashen trailer (timed Xbox One exclusive)
- Life is Strange: Before The Storm trailer (prequel, Episode 1 of 3 on August 31st)
- Middle-Earth: Shadow of War trailer and gameplay (October 10th)
- Anthem (new Bioware IP) gameplay (2018)
Should obviously be noted that the games which are timed Xbox One exclusives didn't outright announce a PS4 version, but it being timed exclusive obviously heavily implies it.
There was also a Minecraft related announcement but I'm not sure if that's on PlayStation platforms. It involves cross-play and Sony isn't too big on PS-XB cross-play. Also included stuff such as 4K, self-made texture packs and player skins.