No one said No Man's Sky yet? LUL
On topic, some of my top choices would be;
The chill/fun life
Indexverse as a mid-tier (level 2-4) ESPer living in Academy City
Nasuverse as the bartender of Ahnenerbe
Muv-Luv universe, Extra timeline, as a student in Hakuryou Academy's class 3-B
Majikoi universe, as a student in Kawakami High School's class 2-F
The "This is cool, but I'm(most likely) fucked"
Muv-Luv universe, Alternative timeline, as a TSF pilot
Nasuverse as a Master
Hellsing Universe as a member of the Wild Geese
GANTZ universe as one of the "Players"
Shingeki no Kyojin universe as a member of the Survey Corps
The "Fuck you I'm a God"
Indexverse as a top tier level 5 ESPer or Magician
Demonbane universe as Demonbane's pilot
Nasuverse as an owner of Mythic Eyes of Death Perception
Hellsing universe as a top-tier vampire
The lewd
Monster Girl Quest universe as a hero
The Lilithverse as any male with influence/power
Any of Otokonoko soft's works as a male
Nekopara universe as a catgirl owner
Yakin Byoutou universe as a doctor