1-30 is a joke. Victoria Island Quests, New mobs by nautilus are great.
30-37 Mushroom Kingdom Questline, Helmet Pepes, Or the lower leveled Kerning Square (Cherry/Mango/W.e bubble teas)
37-50 Drakes, CD's, Monster Park, Kerning square.
50-70 is the fastest at Jesters, Toy Room is viable if chimney is too full.
70-80 Jesters, Sand Rats/ other magatia mobs
80-90 Jesters, Roids and higher leveled Magatia mobs
100-110 Captains And Krus, Dual Ghost Pirates (DGP requires elemental Reset, but great mobbing)