These is my favorites:

1- Black Vulcan (Justice Leauge/Super Friends)
2- Apache Chief (Justice Leauge/Super Friends)
3- Samurai (Justice Leauge/Super Friends)
4- El Dorado (Justice League/Super Friends)
5- Rima (Justice League/Super Friends)
6- Lord Fanny (Invisibles)
7- Mas and Menos (Teen Titans)
8- Martian Manhunter (Justice League)
9- Peguim (Batman)
10- Starfire (Teen Titans)
11- Bestboy (Teen Titans)
12- Superboy (Teen Titans)
13- Darkseid
14- John Constantine (Hellblazer)
15- Rorschach (Watchmen)
16- Swamp Thing
17- Two-Face (Batman)
18- Firestorm (Justice League)
19- Black Canary (Justice League)
20- Blue Lantern Saint Walker
21- Grifter (Wild C.A.T.s)
22- Freefall (Gen13)
23- Zealot (Wild C.A.T.s)
24- Guy Gardner Green Lantern
25- Silk Spectre (Watchmen)
26- Steel (Justice League)
27- Supercyborg
28- Superboy (Teen Titans)
29- Plastic-Man (Justice League)
30- Fairchild (Gen13)
31-Ultrawoman (Lois Lane in the tv show "Lois and Clark")

No guest characters!