With Sony not taking part this year, all I have to look forward to this E3 is Nintendo.
Now, with the lineup they currently have planned for 2019, there's a lot to look forward to for sure. I'm very much eager to learn more about Luigi's Mansion 3, Link's Awakening, and Animal Crossing. Although, with that said, the latter should be a given. Nintendo has had a trend for the past 3 E3s of having one particular game hold center stage. 2016 - Breath of the Wild. 2017 - Super Mario Odyssey. 2018 - Super Smash Bros. Ultimate. This year, that game will most likely be Animal Crossing.
And perhaps we'll get lucky and see first glimpses of 2020 or beyond games like Bayonetta 3 or Shin Megami Tensei V, or even more new announcements.