My list isn't as sexy as Wraith's, but here it is. Arthur's story is basically a modern Camelot take, so its essentially one ongoing epic, so the list is fairly narrow. Jason, owing to his more "episodic" adventures has the longer list.

Because Jason is a mixed bag of Spawn and Robin references, with Marvel and Harvey for umami flavor, I've color coded his.

[color=gold][h3]Aqualad[/h3][/color]
[hider=Allies & Antagonists][color=goldenrod][b]Allies[/b][/color]
[list][*] [b]Tom Curry[/b] - mentioned
[*] [b]Atlanna[/b] - mentioned
[*] [b]Vulko[/b] - mentioned
[*] [b]Garth[/b] - mentioned
[*] [b]Mar (Alpha Flight)[/b] - [i]upcoming[/i]
[*] [b]Namorita[/b] - [i]upcoming[/i]
[*] [b]Krakor[/b] - [i]upcoming[/i][/list]
[color=goldenrod][b]Antagonists[/b][/color]
[list][*] [b]Sardine (Super Friends)[/b] - Reimagined, mentioned
[*] [b]Orm Marius (Ocean Master)[/b] - [i]upcoming[/i]
[*] [b]Jesse Hyde[/b] - [i]upcoming[/i]
[*] [b]David Hyde (Black Manta)[/b] - [i]upcoming[/i]
[*] [b]Fire Trolls[/b] - [i]upcoming[/i]
[*] [b]Slizzath[/b] - [i]upcoming[/i]
[*] [b]The Trench[/b] - [i]upcoming[/i]
[*] [b]Creature King[/b] - [i]upcoming[/i][/list][/hider]
[color=crimson][h3]Spawn[/h3][/color]
[hider=People Jason Annoys vs People Jason Dislikes][b]People Jason Annoys[/b]
[list][*] [color=skyblue][b]Lynne Baker[/b] (DC/Batman)[/color] - mentioned
[*] [color=skyblue][b]Jinx[/b] (DC/Teen Titans/Teen Titans Go)[/color] - [i]upcoming[/i]
[*] [color=limegreen][b]Cog[/b] (Image/Spawn)[/color] - [i]upcoming[/i] 
[*] [color=lightgray][b]Casper the Friendly Ghost[/b] (Harvey)[/color] - [i]upcoming[/i]
[*] [color=yellow][b]Agatha Harkness[/b] (Marvel)[/color] - [i]upcoming[/i]
[*] [color=skyblue][b]Deadman[/b] (DC)[/color] - [i]upcoming[/i] 
[*] [color=skyblue][b]Frankenstein's Monster[/b] (DC)[/color] - [i]upcoming[/i][/list]
[b]People Jason Dislikes and/or Dislike Him[/b]
[list][*] [color=limegreen][b]Angela[/b] (Image/Spawn)[/color] - [i]upcoming[/i] 
[*] [color=limegreen][b]Violator[/b] (Image/Spawn)[/color] - [i]upcoming[/i]
[*] [color=yellow][b]Douglas Carmody/The Bogeyman[/b] (Marvel/Power Pack)[/color] - [i]upcoming[/i]
[*] [color=limegreen][b]Billy Kincaid[/b] (Image/Spawn)[/color] - [i]upcoming[/i]
[*] [color=skyblue][b]Mordred[/b] (DC/Justice League Unlimited)[/color] - [i]upcoming[/i]
[*] [color=skyblue][b]Thanatos[/b] (DC/Aquaman)[/color] - [i]upcoming[/i]
[*] [color=limegreen][b]Overtkill[/b] (Image/Spawn)[/color] - [i]upcoming[/i]
[*] [color=lightgray][b]Hot Stuff the Little Devil[/b] (Harvey)[/color] - [i]upcoming[/i]
[*] [color=yellow][b]Mephisto[/b] (Marvel)[/color] - [i]upcoming[/i] (Shared with everyone)
[*] [color=limegreen][b]Tony Twostep[/b] (Image/Spawn)[/color] - Reimagined as Anthony Cullen, [i]upcoming[/i] (Shared with Half Pint & Mickillenial)
[*] [color=skyblue][b]Sheriff Shotgun Smith[/b] (DC/Batman)[/color] - [i]upcoming[/i] (Shared with Half Pint & Mickillenial)
[*] [color=skyblue][b]Black Cullens[/b] (DC/Batman)[/color] - mentioned, (Shared with Half Pint & Mickillenial)
[*] [color=skyblue][b]Street Demonz[/b] (DC/Batman)[/color] - [i]upcoming[/i] (Shared with Half Pint & Mickillenial)
[*] [color=skyblue][b]Ma Gunn[/b] (DC/Batman)[/color] - [i]upcoming[/i] (Shared with Half Pint & Mickillenial)[/list][/hider]